Yes you've got the right to refuse service, yes customers can be a pain, but it's a customer service industry. You think you're protecting a $8,000 fleet-priced car (which they're going to resell for $6-8000) but the big picture is customers like me who's company quits renting 6-8 vehicles for weeks on end at Enterprise because our employees get jerked around at regional offices when they are traveling. If you don't like dealing with customers get out of the service industry.