I hope the seasonal only rental options doesn't pass.
More options is better than less options. Players renting and testing a card they like or want to test before purchase shouldn't require them to rent for a full season. The daily rental allows for such.
As for cancellations: markets will work that out.
Meaning those renting should take notice of such actors and skip renting from them.
1 DEC Floor was a great idea and cleaned up allot of listed cards that weren't renting.
Splinterlands can also just put a blacklist option for players. Players on the blacklist won't have their cards shown on the market for that player. Although I am sure that if someone proposes this, the whales would be downvoting it and wouldn't pass because it would hurt their pocket.