On: How can phone companies detect tethering?

[Wowfunhappy]

I agree with you overall, but not this reasoning. Smartphones can connect to VPN's as well.

[bradknowles → Wowfunhappy]

Sure.

And anyone who uses a VPN can get themselves limited, just like they were using a laptop, because the carrier thinks you're trying to hide something from them.

[Wowfunhappy → bradknowles]

Have you ever heard of on-phone VPN use being detected as tethering? I'd expect the victims of this to be quite upset!

[darkpuma → Wowfunhappy]

They can, but is it as common in practice? (I earnestly don't know.)

[Wowfunhappy → darkpuma]

Every VPN provider I'm aware of offers either a mobile app or set up instructions for Android and iOS. So while that doesn't really answer your question, I suspect there's a non-insignificant number of mobile VPN users.