They should restrict the size of some of the pax. On a recent commercial positioning flight I had a women who needed two seatbelt extensions shoehorn herself into the midle seat. The FA asked if there was anything else that she could do for this pax, women asked if she could have a first class seat. Then she asked me if i was grossed out by the obvious physical contact, since I wasn't in uniform and was on a paid ticket , I told her I was in fact grossed out. The FA moved me to another empty seat. This women would have been a deadly obstruction in an emergency.