Although I applaud B&M for making some effort to accommodate larger guests, I don't believe the causitive issue has been addressed. This past weekend I visited SFGA, and of course, wanted to ride Nitro. I tried out the "test" seat by the entrance to the ride, and managed to attach the cable to the yellow bar. After waiting in the "fast pass" line for about 30-45 minutes, it was my turn to ride. While I can't say it was easy to attach the cable, it did hook onto the bar...so I let out a sigh of relief and got ready for my ride. That's when I heard "re-check car 6"!! The computer didn't register that the restraint was locked in, and I was forced to get out of my seat. The ride operators were not at all helpful, and they continued to usher me out of the loading platform in a hurry, under the watchfull eye of hundreds of guests. They didn't respond after I told them I had tried the test seat, and fit.
I believe the problem with the cars is the molded seating. It is not easy for a larger person to squish their butt, and legs into a seat designed for someone around 180-190lbs. A compounding factor is the issue of the actual restraint, and the relative shortness of the cable. When a person doesn't fit into the seat properly, of course the bar isn't going to go down as far as it should. Especially on B&M coasters.
By far, in my coaster riding experiences to date, Intamin has the most comfortable, conducive seating for larger guests. Vekoma is not far behind. For that reason, I am looking forward, with anticipation, to riding Millenium Force in a few months!