Is it possible to trick the GoGo Inflight WiFi on airlines into thinking that you have a mobile device instead of a laptop?

It seems like most airlines that offer in flight wireless these days use GoGo. They offer different pricing for mobile and laptops. It seems like they are checking the browser's user agent.

Out of curiosity, is it possible to use a Firefox extension like this one to spoof the user-agent and allow a laptop to access the internet under a GoGo mobile plan? How would GoGo handle something like an IMAP email client, like Thunderbird. Do IMAP clients have a user-agent field as well that would normally identify whether the mail client is running on a laptop or mobile device?