Rent an OP Family for face slaps would be a great business and all, except no one could afford it. The people who could, wouldn't need it.
As for rent a girlfriend, that shit's expensive. Rent a best friend/best man/maid of honor, rent a father, rent a mother, rent a son. All those be expensive as hell.
Rent a son is the cheapest, and the kid is really well mannered too. It's saved me more than once from a clingy thot. They see you have a son and after you tell them the story about having your balls snippet due to this one unfortunate 'accident'. They're out.