mik5: The Gemara in Zevachim explicitly states that if it’s learning B’ones (that you’re thinking about Torah even while trying to avoid it) then it’s okay.
Wolf: That really is a problem. Ba’alei Simcha should be more careful about it or have them play classical music over the speakers in the bathroom to avoid this problem. I once gave this Eitzah to a couple getting married and B”H they listened to me. And people were impressed by the wedding that they had classical music in the bathroom, not realizing (well, maybe some realized) that it was there for Halachic reasons.