There have been times I had to think about which rest room to use, but I haven’t made that mistake.
However, there was a time where I ended up in the men’s room en femme.
I was driving home en femme after dropping my daughter at college (an all day drive). The last rest stop actually on the highway was about 2 hours from home, and I needed to go badly (as well as a last stretch before the final push). I walked into the building, and found the signs for the women’s room. While sitting and doing my business, it occurred to me, Isn’t this the men’s room? I had been in the rest stop before, and the location of the rest room seemed familiar to me. While walking back to the sink, I noticed the urinals.
When exiting the rest room, I realized what was going on. There was a single male attendant there to clean the bathrooms. So at some time before I got there, he made sure the ladies room was empty, and put up signs to temporarily switch the men’s and ladies room. This way he could go in and service the ladies (now temporary men’s) room. The men’s room became a temporary ladies room. So although I was in the men’s room, it was legit. because it was a temporary ladies room.