Or they might take the position that you're liable as long as the cloud you use contains any servers in TX. The theory would be that the existence of those ser

Or they might take the position that you're liable as long as the cloud you use contains any servers in TX. The theory would be that the existence of those servers helps you offer a more reliable service to TX customers, whether or not you actually use them. Probably a weak theory, but TX doesn't seem to care about that. When I used to have a shell account on io.com in the mid-90s, TX started forcing them to charge me sales tax, even though I was clearly not present in TX.