I always try to have the telephone numbers of the airport hotels with me in my organizer, if things are starting to look bad I'll ask if they can hold a room for an hour or two until I see if I will need it. If I can get out on a flight, then I always call back and say thanks, but won't be needing it. I've never been charged if it was just held for an hour or two.

The other bit of advice, when at the counter if you have an e-ticket get a receipt or have it changed into a paper ticket with the full ticket number on it. Should they put you on another airline it makes it much easier to get the miles from your first one if you have the ticket number.