A “Deer Xing” sign isn’t there to tell the deer where to cross the road.
It’s there to let drivers know that this is the spot where deer often choose to cross the road.
Because deer can’t read signs, and even if they could, they probably wouldn’t bother to obey them. People, on the other hand, are far more likely to be killed by hitting a deer than they are by a shark bite.
A good signmaker is aware of “who’s it for” and “what’s it for.” In this case, the hope is that drivers will be more careful.
Too often, signs of all kinds (metaphorical signs, not just physical ones), are simply ALL CAPS YELLING about how the signmaker is frustrated about something they can’t control. If you can’t influence something, why are you yelling about it?