In regards to what I do with renting, once I reach a certain league with my account then I stop playing ranked and cancel all gold card rentals. Keep in mind this is usually with 2+ days left in the season. Then I post them back up for rent. I would never cancel a rental contract within 24 hours of the season ending. I want people to get as high a league reward as they can. I'm all for giving the person who owns the cards the option to choose a fixed rental period to help prevent what you describe in the article.