In all seriousness, no one deserves to pay for a meal and have human semen/bodily fluids inside of it. It is the food equivalent of someone keying your car, only worse.
Behaviour only for PURE scumbags and it really taints whatever collective agreements we have about day to day trust and civility.
I really hope you don't mean this. I really hope you are the kind of person who is willing to handle their beefs man to man as opposed to passive aggressively shitting in their burger.