In People v. Criss, 294 Ill. App. 3d 276, 279, 689 N.E.2d 645, 228 Ill. Dec. 586 (1998), the court held that under certain circumstances, surveillance officers are not required to disclose established surveillance points on cross-examination, so long as the defendant is not denied his constitutional rights by the nondisclosure. Criss, 294 Ill. App. 3d at 280. The surveillance location privilege is not absolute; the extent of the privilege is left up to the trial court. Criss, 294 Ill. App. 3d at 280. A defendant may overcome the privilege by making a strong showing that the disclosure of the location is material or necessary to his defense, and his need for the information outweighs the public's interest in keeping the location secret. Criss, 294 Ill. App. 3d at 280-81. Even where a defendant cannot overcome the privilege, defense counsel should be allowed to cross-examine the officer's observations as to distance, weather, and any other possible obstructions. Criss, 294 Ill. App. 3d at 281.