I sometimes find underwear at my local college gym locker room, and I've taken a few pairs. Recently, I left a pair of Merona briefs just hanging on the hooks at the shower. That was about a month ago. I was there yesterday and that pair is still hanging there. In addition, there's a pair of boxer briefs and some trunks just sitting on the bench in the shower area. I'm thinking I might go back and take them.
I had the privilege of changing with a bunch of college kids yesterday at an event and was impressed with the variety of underwear I saw: clingy trunks mostly, but also one kid (maybe 19) who was wearing simply basic tighty whities. You don't see that much on college guys. It was such pleasure to just be changing and showering with them. I made a point of standing in my jockstrap for a bit; none of the them wear jocks. In fact, I don't think any college guys wear jocks any more. Maybe the football players. Even the lax team I saw practicing made me a little sad; I knew there were no jocks out there--well not real jockstraps---they might have been wear cup straps.