Thanks for the post. Very interesting, however not too worrisome for the majority of the asphalt queens out there. You'd have to do some serious off-roading to achieve that sort of flex.
Another GM infomercial. That's a real unbiased video right there. I'll bet there was no sneaky special engineering involved either. Kind of like, the hamburgers you see in TV commercials always look better than the ones you get at the restaurant.
Sometimes frame flex is wanted and engineered into the vehicle. Just look at the unimog. The frame is part of the suspension. Also I believe that Ford frame has been the same since the late late 90s.