Tethering is using your smartphone as a mobile wi-fi hotspot. It’s a handy way to get online when you’re, say, stuck at the dentist’s office and need to turn in some work. It’s also against the rules for customers with legacy unlimited-data plans from AT&T, for obvious reasons. One customer who has one of these plans is currently fighting with AT&T: they want him to stop tethering, and he says that he isn’t.

Ars Technica took on this question about the fundamental nature of reality and of phone plans, trying to figure out between AT&T and the customer what was happening here. AT&T told Ars that their customer, Evan, “is using an unreleased mobile OS downloaded from the Internet.”

Technically, that’s true, but the operating system on his Nokia Lumia is a beta release from that notorious hacker collective known as… uh, Microsoft. It’s the upcoming version of the Windows mobile operating system, not any kind of jailbreak or exploit meant to get around restrictions against tethering.

While AT&T has increased the soft data cap before Internet access is dialed back to dialup speeds for customers who still have legacy unlimited plans from 5 GB to 22 GB, they stand firm on the no-tethering rule. AT&T says that Evan used used his phone as a hotspot at some time in August, and Evan says that he didn’t.

He can’t prove a negative, and believes that this is a pretext to get him off the unlimited plan. If they want customers off the plan so badly, he wonders, why don’t they just stop letting customers, even grandfathered ones, use it?

Suspicious of tethering, AT&T threatens to kill man’s unlimited data plan [Ars Technica]

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