As Connie points out, "common sense" isn't often so "common" when it comes to rest room use:
"Restroom etiquette is not always practiced by cis women either, although I have to guess that few, if any, of them stand facing the toilet in the stall when they pee. Many do, as do I, squat and hover to avoid having to sit on the seat. Following the rules of etiquette is important for the trans woman, in that it reduces the red flags (go ahead and make that into a tasteless pun, if you'd like). As you say, it's just common sense. Common sense, though, is not necessarily common to ones gender. Maybe, then, a third restroom should be made available to the slobs of any gender(?)
When I first ventured out, it was with a cross dressing social group. They have a long "Rules of Conduct" contract one must agree to prior to joining in outside-the-meeting activities. To me, it was all common sense, and I imagined that there must have been many incidents that led to the writing of this list. I know of one person who was banished from the group many years ago for masturbating in the stall! Again, I'm sure that there have been cis women who have engaged in that activity, as well, but with not such egregious results.
For a trans woman (or cross dresser, for those who would want to make a differentiation), using the ladies room for the first time is often considered to be a rite of passage. It's not necessarily a right of passing, however. For most of us, our outings would be severely limited if we had to pass completely before using the ladies room.
Since the first time I went out in public "en femme", I have used the ladies room without incident. Until all of these "bathroom bills" began, I never really had reservations to do so. A few months ago, though, I had a little scare as I stood in line in the ladies room. A woman left one of the stalls and, while washing her hands, declared that there had been a man in the room. She turned from the sink and looked directly at me, and it was all I could do to make eye contact in return. "Did you see him?," she asked me. Trying to hold my composure and not let on my relief, I just shook my head "no." I wanted to ask her if she meant that it was a man in a dress, but I really needed to pee, so why press the issue (so to speak). "
I too learned the hard way not to automatically think a toilet I was about to sit on was even close to being in "pristine" condition. Although I did know from my days in the restaurant/bar business cis women were as capable as men when it came to trashing a restroom.
My "worst of story" comes from when a group of cross dressers invaded a mixed gay/lesbian bar in Columbus, Ohio years ago. Several of them seemingly took pride in peeing all over the seats, except the two who kept going in to make out.
If it wasn't for low class, some people wouldn't have any class at all!