You can still use one even if they are illegal. You'll just have to mask the tunnel with a bunch of crap clear text traffic. I'm not an expert on doing that, but I know it can be done.
Discussion
This is so stupid.
It’s like asking “How could they possibly make child porn difficult to access?”
You’re ruined by normalcy bias. It actually wouldn’t be difficult, at all.
If you have to route all traffic through a prohibitive MITM, then sure. However, there are less convenient but perfectly usable ways to get around nearly any technical prohibition.