Are people in restaurants really that nasty? Spitting in food and putting snotz?

my husband was a chef and got out of the industry because of things like what youre talking about. He didnt want his reputation to be linked in any way with the behaviour he saw in others. He has seen all sorts of things even ones putting eardrops in food to give people diarhea. My husbands rule is.. if you eat out, and the food isnt quite right.. like the steak not cooked enough... do not ever send it back because you pretty much are guaranteeing that what you get given back will have had something done to it... pretty horrible thought huh