In 1966 I was a kid traveling alone from London to New York with an Air India ticket. British Airways did the check-in. The Agent wanted to charge me "Excess Baggage." I knew that El Al had a flight to New York so I told her I wanted to switch to LY. I also knew that LY did not use British to do the check ins.
She got flustered and told me "You can switch to El Al but I will telephone them and tell them that you are arriving with Excess baggage."
I went to the EL AL check-in and they said nothing and charged zippo.