On a recent TLV-JFK flight, in which Biz Elite had a number of empty seats, one of the pax decided to give himself an upgrade.
An FA asked to see his boarding pass (before take off) and when he presented it, she told him to go back to his Economy seat. He suddenly decided he did not understand English at all.
Unfortunately for him, Delta always has at least two Hebrew-speaking FAs on this flight and one of them told him that he would have to move. He refused.
At that point, he was informed that he would either move or the police would be called to take him off the plane.
Suddenly, that Y seat he had did not look all that bad to him.