Regarding the cabbies, I have always told them to take me to the new convention center. Last year I went there at least 7 times and each cabbie found it without a problem. I would just tell them the convention center and not worry about the Westin.

As for the bill, I have never had a problem getting a bill. If the agent says they can't print it, I just say I will call Amex and have the deny the charge. That usually brings out a manager who finds a way to get me a bill, even if they have to fax it later.