Once when I was hanging out with some friends, I was sitting next to this girl who had dated another one of my friends (we all kind of took turns dating each other to see who best fit), and she made an under-the-breath comment about how he "had a kink for wearing diapers" with a dismissive and negative attitude. Obviously this caught my attention, that someone else I know could be a DL! I asked her to repeat what she said, as if I hadn't heard it, hoping she might expand on it a bit, but she was just like "Uhh, umm, nothing!".
I've always wondered if I just misheard it (although I thought I heard it pretty clearly, the odds one of my friends being a DL are so much lower than the odds of me mishearing), but I've never had a situation to bring it up. He's also kind of a braggadocious asshole and would never admit it (granted, I don't think I would either), lol. I've thought about telling my friends about my incontinence (since that started a year ago or so), and seeing if I can notice any rise out of him, but if I was to do that it'd be more for the benefit of me not having to keep a secret around them. Either way, it hasn't mattered enough for me to spend much time considering it yet, heh.