[abrigham]

They have already started blocking tethering on some phones. My wife's Moto Q9C can no longer tether using the ICS that came built into WM 6.1. She get's an authentication error. Nothing we tried could get it to work and when I called CS, after getting transferred to Advanced Support and trying a bunch of other stuff (including manually re-provisioning the phone) it still wouldn't work and that's when he told me that they are starting to block tethering. This was a couple of months ago, too. I'm honestly not sure how they can tell the difference if you're not using the "Phone as Modem" option in ICS but they obviously can. We installed PDANet (for which I had purchased a license a couple of years ago for my first Moto Q) and were able tether just fine.