Most layer 7 blocking mechanisms look for the SNI header in a TLS datagram or the host header. It's not complicated and trivial to do. Only looking at the host header would be quite amateurish. I'm not a security expert, and even I know this.
CF could use some sort of IPSec or SSL tunnel back to another datacenter to make the origin request. It would add a lot of latency, but it would ensure that local authorities don't mess with the traffic. This was a popular way for CDN's to get around China for a while. I believe one CDN provider billed it as "Secure origin routing." I doubt that they still offer it, as everyone wants to play ball and make money in the end.