Yes, effectively a VPN but I would just call it a tunnel, I don't think it fits the definition of a VPN. I'm not sure if this traffic is encrypted (I assume it

Yes, effectively a VPN but I would just call it a tunnel, I don't think it fits the definition of a VPN. I'm not sure if this traffic is encrypted (I assume it is), but I know GFW filtering happens at egress points so mobile traffic would already be tunneled by then. They could add dedicated hardware at mobile towers to GFW this traffic but I don't think the govt sees a need to. The primary target of the GFW is to stop Chinese citizens from accessing foreign services. Foreigners on foreign roaming data plans are not the intent of the GFW. My bet is that they could filter this, but it's not worth the infrastructure investment.