Ditto on the time thing for USA Transfers. Usually if they tell me a pick up time that is too early, I'll just email them back letting them know what time I want my pick up. IE: For my 7am flight they wanted to get me at 4:00am but I told them to come at 5:00am.... no lines at that hour of the day. They do have the official disclaimer that if you ask for a later pickup it is not their fault if you miss your flight.
And it is true that we did have a 7am flight out of Cancun once. Do yourself a favor and NEVER leave that early. Uuugggghhh!
