In my experience, the "NO" figure should be bent over a bit more in order to project onto the wall behind the toilet as well as the ceiling above. No better memory of working retail than going up to my boss and explaining why I needed to know where the spare ceiling tiles were.
Reminder to anyone still working retail: if your job description isn't "janitor", you don't need to clean that up. It's a biohazard and they can pay more expensive people with better equipment to do it.
Reminder to you that bosses can and will ask you to do things that are not your job. And since you need money for rent and food, you will have to do it. Otherwise, they will probably get rid of you, and will find a plausible legal reason.
Are you aware of the legendary Ryan's Steakhouse story?
Hell, that thing might be an urban legend, but it's supremely well written and if I was in graphic design, that story alone would probably lead me to thinking that selling signs like this would be a good idea.
If you haven't heard it, a web search for "The Steakhouse incident" (with quotes) or "macaroni beef toilet story" (no quotes) will probably turn up yet another re-hosting of it.
The women who hover instead of sitting on the toilet, and leave their pee all over the seat because they are absolutely without empathy for anyone else on the face of the earth. If you are so OCD you cannot touch the seat, for fuck's sake at least kick it up out of the way with your foot.
People from my country don't throw paper in the toilet. It cloggs it up, so instead, the correct is throwing in the trash can. By the way, if this is only common here, then what is the trash can for?
Having seen the occasional superfunded chain restaurant men's room, I know for a fact this sign is needed, and yet probably won't help. I have to imagine the kind of person who will do that to a restroom, and leave it that way, isn't going to see this sign and say "OOOOOH that makes sense. I was totally gonna do that until I saw this sign."
In my mind, I think it starts with one rogue fleck or dribble, causing the next person to avoid and hover slightly, which produces lower accuracy yet, causing the next person to hover even further, which keeps compounding until you eventually get the shitter who actually purchased and ate one of the rotating bubbling skin hot dogs at a previous gas station, and then you get what you're seeing here.
In some countries the toilets are sort of embedded in the floor and you squat over them. There's some evidence that this is a healthier way to poop. But if you've only ever squatted in your life a toilet might be as confusing as the three shells.
Which is interesting because Japan has been pushing to replace all the washiki (squat) toilets in public places. I have a feeling handicap accessibility, aging populations, and (to a lesser degree) tourists are behind this. I hate squat toilets, but I have stomach issues that can make things messy regardless of diet, etc.
I was in a large open plan office a decade ago with a density clearly higher than the 3 cubicles in the toilet facilities could handle.
Somebody with little regard for basic human decency, murdered the shit fairy and their family in two of the 3 cubicles. Words cannot describe the scene that greeted a prospective cubicle user. Imagine 300kg black forest gateaux with pieces of corn distributed throughout being put through a wood chipper. It was quite frankly both terrifyingly grotesque and strangely skillful.
I called property services who to their credit promptly sent up somebody to investigate. I saw them enter, loudly say "Fuck their mother in the arse!" and leave dry heaving into their cleaning cart.
Photos were taken and emailed around to all male employees stating that the "...rancid fecal matter will be genetically tested to determine age, race and dietary preference of the individual involved!!!"
Total bullshit of course, funny as hell though. We had our suspects but nobody fess'd up.
I faked having a colostomy bag after that just so I could use the ambulant toilets. But that's a story for another time.
I've never seen the aftermath of a shotgun spray, but I have seen a giant oatmeal loaf on the seat before. It's part of why my old job stopped letting truck drivers use our bathrooms.
Having worked as a dishwasher in a chain restaurant, whose job it was to clean the bathrooms in the middle of the day after a busload of septuagenarians have done pretty much this: Yes, yes we absolutely need this sign.