From the article: "As it turned out, Coish only had liability coverage, not collision and comprehensive, so he wasn’t covered for theft and was told he must pay Enterprise Holdings $49,832 for the stolen truck."

Well, yeah, don't use liability insurance on an expensive vehicle. He'd be in the same trouble if he'd caused an accident that totalled his rental.

Honestly, I wouldn't mind rental companies requiring proof of full coverage or forcing their own insurance, but that's just me. It shouldn't be a law or anything.