haven't read much of this thread but...
I think flopping on a charge or a block should be perfectly acceptable. those are judgement calls and you should be able to sell them to the refs. however, I think flopping on a flagrant call or something of that nature shouldn't be allowed. for instance, if embiid (player chosen at random) throws his elbows up and misses smart (also chosen at random) by 3 inches and smart flops and starts grabbing his nose, when they look at the replay, smart should be charged a T for acting as well as embiid for throwing elbows in the direction. you can tell a flop from trying to get out of the way in those cases. especially with the nose grabbing.
if a player wants to flop on another call, or whip his head back like he is being fouled when there is a little contact, that's on the refs to get it right. they get paid to tell the difference. I wish our players were better at selling stuff like that.
basically, if you want to flop a charge, go right ahead. if the refs can look at it on replay, they should be able to give a T to the faker. I have no idea if this is actually a rule, I assume it falls under unsportsmanlike behavior, but ive never seen it called.