One of the reasons why it works in Japan is the insane cost of taking a cab to an airport like NRT. Here in the US it's much more reasonable to take a cab to the airport and why if i'm taking a taxi would I need a service like this? If it's going to cost me lets say $10 to send my bags ahead plus $15 to take public transit to the airport why not just take the $35 cab ride?
Cheers
Howie