Most airline Conditions of Carriage would ensure that the entrie field was in the airline's favour. I would imagine that any gesture made would be entriely at their discretion and then only in the spirit of good customer relations. I think that the United story is the stuff that nightmares are made of, sadly how many people have had emergency calls from a hospital only to get there too late because of traffic. I think that given the circumstances United might have beena little less parsimonious, but then the problem is that less scrupulous people use this reason each and every day.