Perfectly logical

Overheard in the gym locker room:

"The bottoms of my pants are all damp. And my locker is bone dry. And when I put them in, they were dry. Someone has been in here."

"Is anything missing?"

"No. But a few weeks ago I gave the manager my lock combination."

"Ooh, you better get a new lock."

Yes, of course. Because the first thing the gym manager would do if he could open lockers is to reach in, dampen the hems of your pants, and then lock it back up again.