Put up a “wet paint” sign and people touch it just to check. Telling people not to do something can make them curious.

A prohibition carries information, and sometimes the information is more interesting than the rule. Being told not to do something points straight at it, hands you the idea and dares you slightly, which is why bans so often advertise exactly what they meant to prevent. People dislike being managed, and the resistance is usually about the telling rather than the thing.

When you want somebody to stop, give them a reason rather than an instruction, and make the better option the easy one. If you notice yourself wanting something mainly because you were warned off it, ask whether you wanted it before the sign appeared.