This reminds me of Mr. Rogers’ “Freddish,” or his specific way of talking to children. One of his principles was this exact point: only phrase things in the positive. Thus, rather than saying, “Don’t cross the street by yourself,” word it more like, “Ask an adult before crossing the street.” There were several other components to Freddish, like emphasizing the benefits of listening to adults and praising the child for their compliance, but “phrasing things in the positive” was the one that stuck the most in my mind, and is the most germane to this discussion.
(I think I’ve also heard something similar regarding e.g. warning signs, that positive statements like “Stay away from the wires” are more effective than negative statements, like “Don’t touch the wires,” because your brain basically ignores the negative part of it. “*mumble mumble* touch the wires? Don’t mind if I do!”)
Do you also believe we should revert “you” to “thou,” “you,” and “ye?” Because “you” has the exact same problem (gender-neutral, used for both singular and plural cases), but most people seem to struggle through it just fine. (inb4 “y’all” or “yinz,” which are acceptable in their respective dialects but don’t seem to be making progress in universal usage).