I've worn them in the locker room many times. There's been from one to a dozen guys around when I've dropped my pants and been in just my thong. Nobody has ever said anything, actually. I've gotten a lot of friendly smiles, some blank stares, and some confused looks. I only wear women's thongs and g-strings, so guys definitely notice.
There was one time I was getting changed around a corner and had dropped my pants and taken off my shirt so that the only thing I was wearing was a satin pink Victoria's Secret v-string (the one in my profile pic). I didn't hear them coming, but two guys popped out from around the corner heading to their lockers and the first thing that they saw was me standing there in my little pink thong. The shock on their faces was amazing. I turned around peeled my thong off and let it drop to the floor and kept changing. They couldn't help but stare at me. The rush from that one was intense.
There are so many other times that I could write about too. Hard now just thinking about it, lol.