the plaintiffs knew enough before filing to recognize that they were doomed to lose, but the district court disagreed and declined to award sanctions. In this case, as in Sam-tiels, we hold that the decision of the district court was not an abuse of discretion. Sanctions are not appropriate when the plaintiffs’ pretrial inquiries into the factual and legal bases of the complaint are sufficient. Kraemer v. Grant County, 892 F.2d 686, 689 (7th Cir.1990) (per curiam) (stating pretrial investigation into facts and law need merely be reasonable under the circumstances). The district court, recognizing the difficulty in proving conspiratorial agreement, did not abuse its discretion in concluding that the plaintiffs’ claims were reasonable at that time and under those circumstances. See id. (<HOLDING>); see also Smith v. Our Lady of the Lake Hosp.,
recognizing difficulty of evaluating judges demeanor upon appellate review recognizing that proving a negative may be difficult holding that the notion of enterprise conspiracy has largely rendered the old distinction between single conspiracy and multiple conspiracy irrelevant to rico conspiracy charges holding that in a conspiracy case venue lies where the conspiracy agreement was formed or in any jurisdiction where an overt act in furtherance of the conspiracy was committed by any of the conspirators recognizing difficulty in proving conspiracy