Yeah, I have several issues with that video. Both from Six Flags and Bybee.
I'm calling buffoonery on behalf of the riders - you'd have to be willingly or complacently stupid to not get your leg locked into those restraints.
Of course, doesn't excuse terrible operations, though. Sensors to detect a rider's leg would be a nightmare - you'd have to also then be checking that someone was in the seat. Generally the assumption for the manufacturers is that the operators follow the guidelines.
Either way, not a B&M issue.