I think 24 hours is fair. What you could do as a renter is to just wait until there is less than 24 hours left until season ends.
A function that would need to be entered in order to thwart this would be some kind of pre-selected option where the person renting out the card picks a lock-up period that is longer than 24 hours.
I did that one time but took me a couple hours to rent all cards. It's hard to finish the transactions when bots are taking the rental market.
I think your suggestion can be good. But a maximum lockdown period is necessary.