Why not agree to let them schedule meetings at least 24 hours in advance during office hours instead of you sitting there waiting? Pull versus push is always better. Then just bill them the regular rate.
"The limitations come from what people actually do with computers, as opposed to what the marketers expect them to do. On the whole, people don't want to lug a computer with them to the beach or on a train to while away hours they would rather spend reading the sports or business section of the newspaper. Somehow, the microcomputer industry has assumed that everyone would love to have a keyboard grafted on as an extension of their fingers. It just is not so."
Makes me think they knew something about work life balance that we don't.. or maybe it's just not work anymore but a way to live.