In general, I think an "excuse me, may I jump in here?" would go a long way. Far too many crews fail to do that and just cut right in without even an acknowledgement of the passengers behind them. (Not accusing you, Josher747 but just a general observation).
It will be nice when more airports adopt the known crew member thing so we don't have to worry about it.
I like that. I don't begrudge the crews the right to line jump, but the aove quote is the proper way to handle it and I'm going to start calling out crews exactly as above who rudely use this privelage