I don't think the general public, or even most enthusiasts, understand and appreciate the technology and strength design that goes into lap bar restraints. They simply don't fail like everyone likes to imagine. They are over engineered many times over any standard design loads, and high tech sensors make sure they shut properly and stay shut until the train re-enters the station.
I'm almost certain that the little seat belts on wildfire and other B&M's are just for safety theatre. They give an appearance of standard protocol and make riders feel safe because they have someone coming around to look at them rather than just watching the sensors which are what really do all the work.