[Nasrudith]

If they can control all outgoing points they can control ISP access completely. VPNs wouldn't help as they would still need an out of country connection.

However satellite or other wireless internet not under their control would work unless enforced ad bacculum or through jammers. Anything which depends upon external international IP addresses would break.

VPNs and related would only come into play with unauthorized international connections and the forwarder so it appears traffic is to another domestic address.