While i don't doubt that the OP is telling the truth, i don't buy the theory in general. Sounds like a CM who didnt know what they were talking about, or didn't feel like explaining why they didn't hide the brushes on a given day. According to a friend who was a CM at Tom Sawyer Island last summer, there are many days where they don't bother for whatever reason, or simply don't have time to hide the brushes.