I have a Motorola Droid 1 with Android 2.2 on it. I found something odd that I don't understand why it works.
If I plug my phone into my home computer which is Windows 7 and I turn on the tethering ability, I am met with a Verizon captive portal and it tells me I need to pay for a tethering plan (which I don't have).
Now the weird thing, if I plug the same phone into my Ubuntu 10.10 laptop and enable tethering it works and can get on the internet with no captive portal showing up.
The only thing I could notice that was different about the connections was Windows connected to the phone with an NDIS driver and Linux connected to the phone with what I think is a raw device mapping.
Would that have anything to do with it?