We always took it pretty easy on eachother, esp after a dude broke his collarbone once.
I have no idea how rules are now but when I played Sanda there was a rule specially for this: while throwing no knees were allowed to touch the round or it be disqualified throw. (to keep the worst throws off bay)
We then proceeded to learn how to execute a horsesweep (typical cma move, right?) that would be lead in with an overhand, the over hand would plunge in there and steer the body over your leg.
I hated that throw wbecause its really easy to lose balance yourself and your angle has to be perfect for it to work.
I've seen numeral occasions where the victimer outta reflex with hug the guys middle and both would fall.