Always felt the best reaction for any fan base to show to a player that left their city on bad terms would be to simply pretend like he's not a big deal to them. That's the ultimate show of disrespect to the player, showing him that you don't care that he's gone or coming back or anything about him. That he left no legacy to the fans here.
I've never really seen a fan base pull this off for any player of significance though. I'm also certain an NBA fan base won't be the first to pull it off.