I've noticed on some Right boards, the discussion on this has taken the form of, "who cares, politicians families always get to travel for free with them, that's just the way it works".

No, that isn't how it works.

Members of Congress, for example, have to pay their own way when they bring their children along on official trips -- or reimburse the government for travel by their kids on military aircraft, lodging in embassies, etc. Apparently the law lets them have a spouse along gratis. Even Cabinet secretaries don't get family perks; Rumsfeld apparently always reimbursed the Pentagon when his wife travelled with him on DoD aircraft.

The president (and VP) family are different due to Secret Service protection; they can fly govt aircraft free.

In my job I've worked with not one but two Air Force One pilots, both of whom confirmed that they've seen both the Clinton and Bush WH being quite careful about tracking family members going along on trips, who was "offical" and who was not, etc., and yes the top staffers and pols do indeed have to reimburse the govt.