How would effective prohibition work? Beams are directed enough to make them hard to find from a frequency perspective. Payments will probably be possible in BitCoins at some point given Teslas move in that direction. Controlling the import of hardware seems like a way to do it, but I bet it would still show up everywhere.
This has played out many, many times in history and it's generally successful.
Yes, it's often not perfect. There are small numbers that slip through the cracks. But as soon as it's any significant number the crack will get closed. c.f. great firewall of china, north korea anything, various European data location requirements, russian internet payments and search, etc etc etc etc.
More feasible attacks would be hacking the satellites or ground systems, RF jamming, or just locating users on the ground by their RF emissions and throwing them in the gulag. Or how about holding the Shanghai Tesla factory hostage? Less fancifully, China can put pressure on SpaceX via the ITU. There are plenty of options for China and there is zero chance SpaceX will try to break Chinese law.
Every country, US included, would pressure SpaceX to stop operating in countries that don't want it if it were to result in any debris.
no no
no no no
please. if you want to make Starlink illegal what you do is state Starlink is illegal and maybe make it illegal to pay Starlink. that's a lot cheaper and doesn't piss off the international community.