To be clear, I am in favor of penalizing flopping. I don't like it in general, and I think it leads to injuries. I also don't think the current rule will stand up to the legal challenge from the players association, as these penalties were not included in the new CBA. As of now, however, the rules are still in effect. The league issued some clarification of what will and will not be called.
“The main factor in determining whether a player committed a flop is whether his physical reaction to contact with another player is inconsistent with what would have been expected given the force or direction of the contact. For example, a player will be considered to have committed a “flop” if he falls to the floor following minimal contact or lunges in a direction different from the direction of the contact.