In Anderson v. Cryovac, 862 F.2d 910, 923 (1st Cir. 1988), a defendant accused of polluting groundwater by discharges from its tanning operation failed to disclose a groundwater study it had obtained that gave some support to the plaintiffs' position. Anderson, 862 F.2d at 913-15, 922-23. The defendant argued against sanctions for its nondisclosure by pointing out that the plaintiffs took a different approach during discovery and trial, adopting a strategy that the report would not have impacted. Id. at 931. The Anderson court responded: Beatrice urges that, because plaintiffs previously paid comparatively little attention to the tannery discovery, we are free to conclude that they would have followed the same strategy even if the Report had been timely produced. This exhortation strikes us as idle persiflage. Pretrial discovery follows no set course. An able litigator builds on the information available from time to time, changing direction as new leads emerge and old ones wither. Elementary logic suggests that plaintiffs likely slighted the tannery because they had no evidence, beyond guesswork and surmise, to show that it contributed to the pollution. The report could have filled this void . . . .Id.