A rental is more of a 24hr payment if you insist it's a 24hr unbreakable contract. There is nothing more than that. That's all it is.
Rental storage escrows are used to assist with those 24hr contracts. You store money in escrow in case that card is available during the next 24hr period then that escrow pays again.
There is no such thing as a multi-day rental just doesn't exist.
Auto rentals is saying don't worry about putting your money in an escrow we'll use it as needed and we won't look at just one card from one owner but if that one goes away we'll grab another one and we'll keep reneweing your rental as well.
So, what I understand is that the first 24h are obligated and the rest are optional? Thank you very much in advance!!