You are worrying too much buddy. If China does go through with the ban, the mining companies like Bitmain etc won't just shut shop, but would relocate to other countries where they can continue their operations smoothly in a legal manner.
Relocation takes time unless it was done years prior to that announcement. During those time, when China (assuming) ban's mining, the hashrate will heavily goes down making the next mining for block difficult, if a block is yet to be mined, transaction will not be confirmed so this means there will be tons of unconfirmed transaction piling up the blockchain. This will greatly affect the Bitcoin industry. This happen before and we see users competing for the transaction fee making the price of tx fee bloated to the point that it is more expensive than local remittance fee.
No any country is allowed to banned miner in any country you can mine easily and you can withdraw it from an other location
Is there a law that support this claim?