Molten, why do you compare things that have absolutely nothing to do with each other?
See, here is why this comparison does not work.

A man driving a car does not WANT to go off the bride. so, if by chance he comes close to it, a barrier will help to prevent the worst.

A man going to a prostitute WANTS to go to her. IF he is already in a relationship, he will think he can get away with it.

And if there were not prostitutes, men would invent them. lol