They set a lot of screens, and Klay and Curry are some of the best shooters to take advantage of them. Most of them are very solid, legal screens, but Bogut and Green set very dirty screens by "stumbling" backwards into the defender's path or outright holding jerseys/bear hugging defenders. Those have to be cleaned up. I'm also not a fan of Curry's screens where he sets them and falls on contact, earning a defensive foul. You're a small, expect to get hit hard if you set a screen.
Splitting hairs here, but I would say half of them are. Then 1/4 are questionable, then 1/4 are blatantly wrong.