Another thing: don't assume that these marshals are untrained or badly trained louts. I'm certain that there are some -- good cops don't like those any more than you do -- but the vast majority of cops are good people and good at their job. Trained sky marshals are cops, but given more training so that they can act independent of backup and a base of support. They travel incognito, in civilian clothes. They might be on your flight or they might not.