I am sure that My Keyless remotes are very reliable on most American cars, as they usually will accept up to 5 different codes, and programming at the dealer is not really a problem. I work at a Ford dealership and we do them every day.
But, I still think someone is not telling the truth about these Porsche remotes, either My Keyless or the stealership. How different can they be? They are just bloody remotes for a car, not the key to an ICBM!