I gave this some thought when I was still flying, and I did wonder about arriving back at, say LGW or MAN (before the second runway was built) at peak periods, with management trying very hard to get us to carry ‘plog’ fuel.
My concern was that if the main drag was blocked then all would have to divert. But to where, given that Liverpool, our primary diversion would be very busy with the lowest cost carriers? Leeds would have very little capacity to offer and Doncaster had not yet opened. Much the same with LGW and the airfields there.
I reckoned there would have been some very tight ‘sphincters’.