There is no reason for it to do this, as the kebab machine only spins in order to turn the meat in front of the heat source, and when there are no more customers to cook for there is no point in cooking more meat. Also, health and safety rules normally require that cooking implements are cleaned at the end of the day, so you would have to turn the machine off anyway.

Kebabs are mainly made with lamb; not the most expensive cuts, but most of the meat is perfectly healthy. It's minced and mixed with breadcrumbs and other ingredients to make it stick. The kebab machine is usually called a spit or spike, and people are more and more buying their own to use at home, especially for barbecues. In fact you can make something like a kebab by mixing the meat yourself and cooking it in the oven - there is an example here - but for the real thing, you have to buy a machine.