Personally experienced this 3/04. Had made a car reserve w/ National via their 800 number and was told they did MIA-pier suttle. When I called the airport location direct to confirm the shuttle found out they DO NOT shuttle to the pier. Somehow they manage to do it from FLL though. Something about "security." Same happened with Budget. I ended up going with Alamo and they were great. It absolutly amazed me that huge national agencies like Budget and National did not offer this service while little guys like Alamo, Thrifty and Dollar do, in adition to Avis and Hertz ($$$).