Teach instead of warning

Caution signs aren't there to prevent catastrophe.

"Do not use elevator in case of fire" will not help during evacuation and will not get any attention on normal days.

You hang one because you don't want to take initiative. You hang one because you flinch from accountability. You hang one just to say: We told you so!

What is the alternative then?

Education.

You teach those who you seek to serve instead of instructing them. Then you engage. And, then, shortly thereafter, you might not need to hang warnings anymore.