In People v. Bruner (1995) 9 Cal.4th 1178, the California Supreme Court acknowledged that it is not always a straightforward matter to determine a defendant's entitlement to presentence credits under section 2900.5 where multiple proceedings are in play. But in order "'to provide for section 2900.5 a construction which is faithful to its language, which produces fair and reasonable results in a majority of cases, and which can be readily understood and applied by trial courts'" (Bruner, supra, at p. 1195), the Bruner court developed a rule of strict causation for cases where the same conduct is implicated in multiple proceedings. It said, "where a period of presentence custody stems from multiple, unrelated incidents of misconduct, such custody may not be credited against a subsequent formal term of incarceration if the prisoner has not shown that the conduct which underlies the term to be credited was also a 'but for' cause of the earlier restraint. Accordingly, when one seeks credit upon a criminal sentence for presentence time already served and credited on a parole or probation revocation term, he cannot prevail simply by demonstrating that the misconduct which led to his conviction and sentence was 'a' basis for the revocation matter as well." (Id. at pp. 1193-1194.) The Bruner court further approved of a number of decisions which reasoned that a prisoner's "criminal sentence may not be credited with jail or prison time attributable to a parole or probation revocation that was based only in part upon the same criminal episode." (Id. at p. 1191.) In other words, "a prisoner is not entitled to credit for presentence confinement unless he shows that the conduct which led to his conviction was the sole reason for his loss of liberty during the presentence period." (Ibid.) In Bruner, a warrant issued for the defendant's arrest for three alleged parole violations: absconding from parole supervision, theft of a credit card, and cocaine use based on a positive urine test. (Bruner, supra, 9 Cal.4th at p. 1181.) When parole agents served the warrant, they found rock cocaine in the defendant's possession. The defendant was cited for possession of cocaine and released on that charge on his own recognizance. Nonetheless, he remained in custody under a parole hold. The Board of Prison Terms revoked the defendant's parole based on the three alleged violations and his possession of cocaine, and imposed a prison term of 12 months. While the defendant was serving that term, he pleaded guilty to the charge that he possessed cocaine, and was sentenced to prison for 16 months. The trial court found that the defendant was not entitled to any presentence custody credits on the current charge. (Id. at pp. 1181-1182.) The defendant appealed and the Court of Appeal agreed in part with the defendant that he was entitled to presentence custody credit, but only from the time of the formal parole revocation. (Id. at p. 1182.) The Supreme Court reversed the judgment of the Court of Appeal. (Id. at p. 1180.) After acknowledging the potential unfairness of the strict causation rule it applied, the Supreme Court explained, "it arises from the limited purposes of the credit statute itself. The alternative is to allow endless duplicative credit against separately imposed terms of incarceration when it is not at all clear that the misconduct underlying these terms was related. . . . Such credit windfalls are not within the contemplation of section 2900.5." (Bruner, supra, 9 Cal.4th at p. 1193.) Responding to the suggestion that a rule of strict causation in these circumstances worked an undue hardship on defendants, the Court noted a "defendant's burden, while onerous, is not necessarily impossible." (Id. at p. 1193, fn. 10.) Thus, a defendant in custody on multiple causes, such as parole violations and new charges, bears the burden of establishing that he is entitled to presentence custody credits. (Id. at pp. 1193-1194.) In People v. Stump (2009) 173 Cal.App.4th 1264, the defendant was convicted of driving under the influence of alcohol with a prior felony within 10 years (Veh. Code, 23152, subd. (a)), and driving with a blood-alcohol content of at least .08 percent with a prior felony within 10 years (Veh. Code, 23152, subd. (b)). Stump was arrested on July 16, 2006. At the time of his arrest he was on parole with special conditions prohibiting him from, among other things, drinking alcohol or driving without his parole officer's permission. Stump was found to have violated the terms of his parole not just by committing the two charged offenses, but also for drinking alcohol and not obtaining the permission of his parole officer before driving. (Stump, supra, at p. 1268.) Stump was arraigned "with respect to the July 16, 2006 incident" on December 20, 2006, and remained in custody through the date of sentencing in May 2008. (Stump, supra, 173 Cal.App.4th at p. 1268.) He was awarded credits for the period of December 20, 2006, through sentencing, but denied credits for the period of his prearraignment custody (i.e., from July 16, 2006, through December 20, 2006). (Ibid.) On appeal, Stump challenged the court's failure to award credits for his prearraignment custody, asserting that this period, "was 'attributable to proceedings related to the same conduct for which' he was convicted" because "there was only one 'single, uninterrupted, incident of misconduct,' and '. . . a single episode of criminal behavior may not be parsed into separate acts in order to deny the award of credit for revocation custody . . . .'" (Stump, supra, 173 Cal.App.4th at pp. 1268, 1271.) The Fourth District Court of Appeal noted that Bruner was not "directly on point" because "the decision in that case, inasmuch as it addressed only a fact pattern with completely unrelated incidents--alleged parole violations and a subsequent cocaine possession--did not address a fact pattern such as the one before us, where all of the acts in question were temporally related." (Stump, supra, 173 Cal.App.4th at p. 1271.) The question presented, the court stated, was "how the Bruner 'but for' test should be applied when a defendant engages in a course of illegal conduct, such as drunk driving, that encompasses certain independent acts, none of which would be illegal per se, but each of which happens to be a separate ground for a parole violation, such as driving (without parole officer permission), or consuming alcoholic beverages in any amount?" (Ibid.) The court answered that question as follows: "In the case before us, the conduct for which defendant was arrested gave rise to two drunk driving charges (violations of Veh. Code, 23152, subds. (a), (b)). It is not the case that 'but for' a drunk driving charge defendant would have been free of parole revocation custody. He still would have been held for driving, which is not necessarily a crime in and of itself but may be, and was here, a parole violation. Likewise, he still would have been held for consuming alcohol, which is not necessarily a crime in and of itself but may be, and was here, a parole violation. Penal Code 'section 2900.5 did not intend to allow credit for a period of presentence restraint unless the conduct leading to the sentence was the true and only unavoidable basis for the earlier custody.' (Bruner, supra, 9 Cal.4th at p. 1192.) . . . the conduct of driving under the influence of alcohol, for which defendant was sentenced in the underlying action, was not the 'only unavoidable basis' for the custody. The act of driving without permission was a basis for the earlier custody. The act of drinking alcohol, irrespective of driving, was a basis for the earlier custody. '"Section 2900.5 does not authorize credit where the pending proceeding has no effect whatever upon a defendant's liberty." ' (Id. at p. 1184.)" (Stump, supra, 173 Cal.App.4th at p. 1273.)