Unless the person behind the airbag is smaller than the 5th %ile female (ie 5'2 100lbs) I wouldn't worry about it too much. I myself am not a fan of airbags since I'm of the belief that airbags were mandated to try to protect people who wouldn't wear their seatbelts. I wear mine and if it were practical I'd wear a 4 or 5 point restraint, but I'm digressing. As long as you're wearing your seatbelt, the impact of the airbag will minimized...

Even if the airbags deploy hard (and I haven't seen the studies one way or the other), I'd rather have a broken nose and walk away from my mercedes, than be in a car with a softer deploying bag with my legs pinned needing to be cut out of what had been my car - since we're considering worse case senerios.

In a nutshell:
Leave it connected, don't worry about it. If you get in a wreck, and physical injuries sustained caused by the bag will be miniscule compared to getting to deal with "premium boy" down at the insurance office.