Of course the pax is a safety hazard. That's why you check and if the seatbelt won't fit, he doesn't go. Understanding the reason is important. The man does it because he fears that if he can't go, he will be fired. When it comes to his livelihood, well, nothing bad ever happens while flying, right?
Reducing the overall weight of passengers is great for increasing productivity, and for reasons of safety, companies need to stipulate that passengers that fly offshore need meet specific size requirements. The pilot should be the last level of safety in this case, not the first.