Why don't petrol stations have an exit barrier to stop people driving off without paying?

Posted by FuckingPope@reddit | AskUK | View on Reddit | 185 comments

Sorry if this is a silly question, but I heard on the radio today that drivers leaving petrol stations without paying has gone up loads recently. But i thought that surely an easy fix for that is a barrier, like you get at parking, that would at least lessen the chance of cars driving off without paying? (so attendant inside can lift the barrier after payment is received) Is this a thing in any other countries? Is there a reason it isn't done?