Have you tried it? I tried it for a minute or two and didn't think much of it. I have unlimited data, so it doesn't even show how much I've used so that I know when I'm near the "limit." I don't do a lot on my phone, and turned off HD on the youtube app, so I don't think I'll get anywhere near 15 gigs. It happened to me once, before I turned off HD, and I definitely don't want to experience that again.
Authorized Service Provider (Contractor) for MTS Allstream. Any views expressed are my own.