Originally Posted by danmcq
How are you going to be able to use streaming media services (Pandora/Spotify/etc) when you are connected to a wifi access point with no internet service? The AirPort express won't have access to the internet, and when you are connected to the AirPort with your iDevice, that it going to be your default route. Have you considered this?
Yes, there is a trick! You can be connected to wifi AND still pull data from 3/4G. I forgot now exactly how I did it but it just takes some googling.