I have found the results vary by restaurant. Some restaurants actually have one specific table that is the Fine Dining Table. If its been reserved by another cardmember, there will be nothing available for you. At those restaurants when it is available you always sit in the same seat! At other restaurants they just give AMEX preferred reservations. So you can usually do better than calling on your own. Finally, there are some restaurants which do not seem to do anything special, and it is amazing that AMEX does not boot them off the list. AMEX calls the restaurant direct (you can hold while they do so). Before doing so they verify who you are, that you are a cardmemeber, etc. I have never received special treatment because of AMEX upon arrival at a restauant.