I don't get it. Is this list based on people who cancel a contract at any time in the season? Or at the end of the season?

I rent out quite a good number of cards. I don't cancel rentals three days before the end of the season. But at the beginning and during the season, sometimes I need to change my rental prices (supply/demand, changing DEC price etc, you know?!). If a card has been rented out for 30 days, for example, I need to cancel that contract. Does that make me a 'bad' renter? Even though I refuse to cancel contracts at the end of the season, because I don't think I should maximize my profits and double my renting prices, just because I can - leaving renters without collection power right at the end of the season?

People have the right to cancel a contract - both renters and people who rent. There's no need to make a so called 'blacklist' when people are following the rules of the system. If you want to make one, make one for yourself.