Yes, there is a certain percentage of disconnects to successfully completed games that will restrict an account. The players get placed into a pool of other disconnecting players until their percentage falls back below the level.
I have no idea what that level actually is.
People seem to intentionally disconnect frequently, which makes me think that nothing really happens to members who intentionally disconnect despite the note you receive about how violating the fair play policy can lead to an account being restricted. Is there any percentage of intentional disconnects that actually leads a player to having their account restricted? Or is chess.com, which I love, more interested in collecting dues?