And the second pertinent point is if the renter/buyer violates the conditions of the lease (whether it is a CD or a car – i.e. he agreed to be the only driver but allowed a relative to drive the vehicle in violation of the rental agreement), what halachic recourse is the owner entitled to from the renter?
The point was made above that the only halachic recourse is to reverse the original transaction. If it is something more than that, is there a source for that?