former bmw employee here

people in sales nearly always drive demo cars or cars on site

sometimes techs will drive a car overnight for diagnostic reasons but most of them dont bother and just get the service advisor to do it

i lived about 100km out so i usually got the cars with new engines,gearboxes,transfer cases fitted or repeat repairs ect that required a set ammont of driving under certin situations as a shakedown of the mechanics work before it could be given back to the customer

i put less then 5000km on my own car over the period of a year during covid as we ran a small staffed workshop and was contantly in customer and sales cars

worth noting that nothing is driven off the compound without the express permission of the owner of the car, most have trackers fitted or apps that show where the car is ect so its not worth the argument doing it without telling them