It's not clear that new TrueBlue member Mickey A. Mouse at 123 Cherrytree Lane, Nowheresville, Mississippi, would be a net gain for the airline.
However, if you really want to monetize Wi-Fi then you could offer tiered service. The free tier would be capped at 1.0 Mb/s (for example) — enough for 360p YouTube and low quality Netflix — and the paid tier would be uncapped. There's already passenger competition for bandwidth, so a simple tier offer like this one would probably improve the average experience for everyone. The uncapped bandwidth tier could be free for elite TrueBlue members, Mint and future first class passengers, and (for a "promotional period") all TrueBlue members. But in order to prevent the "Mickey A. Mouse" problem your TrueBlue number would have to be connected to your seat number. You'd log in using your surname and seat number if you want the higher tier, maximum 2 logged in devices per seat. No fumbling for TrueBlue numbers, passwords, ticket record locators, or anything else. It needs to be simple. And if you don't want to credit your JetBlue flight to TrueBlue, you still can enjoy the free 1.0 Mb/s capped bandwidth tier.