This is a little quirk of mobile deal-making I wasn’t aware of. Gadgetwise noticed that on the AT&T Captivate (which I recently reviewed), launching the included MobiTV app while connected to a Wi-Fi network prompts you to disconnect, and then warns you in all caps “THIS PRODUCT WILL USE A LARGE AMOUNT OF DATA AND YOU ARE RESPONSIBLE FOR ALL DATA CHARGES.”

Sure, and usually that’s why they ask you to connect to your Wi-Fi: so it doesn’t burden the network and/or use up all your data (at which point you inevitably come crying to them). So why does this one tell you to shut it down?

It turns out that the app maker, the service provider, and probably the handset maker all put their heads together and decided that their included TV streaming app would be network data only — in hopes that people would upgrade their data plan to accommodate all that bandwidth they’re using. Pretty evil, if you ask me, but they do warn you what they’re doing.

It’s kind of ugly, but the fact is these are the deals that get cut so you can pay $200 for a $600 device. No one’s forcing you to use them, just like no one’s forcing you to click on ads. And if you don’t like it, get a custom skin like LauncherPro and just hide the suckers.

Update: Craig from MobiTV notes below that the app does in fact work over Wi-Fi, but content restrictions (i.e. their contract with so-and-so content provider) prevent you from doing so on a few devices, like the Captivate. So it’s not a plot to sell more data.