In times past I've been asked to turn on a laptop (which actually could have been a problem as the battery was in *VERY* bad shape. It didn't even get very far into the boot before shutting down for a lack of power. Had the next airport wanted to see it also... Since I always ran it plugged in the battery didn't bother me otherwise.) and I've had an idiot unhappy with my camera because they couldn't see through it--SLR with the lens not mounted.