1. It is somewhat defensive, but you can shoot out of it. Braeden Davis did once or twice today. A lot of guys that work from their knees like to counter on a shot. So if your opponent is active, you can generally avoid a stall call from your knees (as long as you counter). If your opponent on his feet doesn't sheet, and you stay on your knees, you likely will be hit with a stall call.
2. It can be confusing. The calls used to be left solely up to the judgement of the ref. To promote more action, the rules have been tweaked some that there are some mandatory stall calls (backing off the mat, holding onto the legs with no hold above the waist for 5 seconds, etc.) So while a wrestler can be more active and more aggressive than their opponent, they can do one of the aforementioned acts and get hit with a stall call. It doesn't seem balanced, but the ref is simply enforcing the rules. This year, they also put an added emphasis on the guy on top working for a tilt. Kerk has been hit with stalling several times this year due to that (and was tonight in his semi), as he we pull his hands off and do little, to encourage the bottom guy to make a move (when they are doing nothing), so that he can use that move to try to turn them. Alas, that invites a stall call on him, and multiple refs have done that.
I hope that helps
