Some users require TP goes in a bag. Yuk.
That was exactly our reaction during our second trip to Isla Mujeres. The first time, we stayed in one of the standard tourist condo hotels. While we were there, we met a lot of great people who lived on the island who introduced us to the possibility of renting small apartments. Much cheaper, a more authentic experience, and in general just a more of an "escape" type of vacation; we were more able to immerse ourselves in a different way of life than the typical rat-race for more crap (no pun intended) at home.
First eye-opener was the requirement of the apartment owner to not put anything in the toilet that you didn't eat first, including used toilet paper. My wife was so grossed out by the prospect that we almost bailed out and went back to a "real" hotel. Fortunately, we came to our senses. It's no problem at all, doesn't stink, no more difficult.... it's just something we weren't used to. I mean, without getting too indelicate, you have to handle the toilet paper once you use it; what's the difference where you drop it? Put it in a garbage can/bag, twist the bag close, and go enjoy the rest of your day.
We felt really stupid the second day, and apologized to the owner for our initial reaction. She laughed, saying "Don't worry about it; I would have thought you were one strange gringo if you WEREN'T surprised at first." Sweet lady.... like everyone else we met on Isla. We've been back a ton of times, and always stayed in private apartments since.
Customs are just customs. That's all. Easy to change.