To issue BTC, the network nodes require a valid cryptographic signature for the transaction that consumes that UTXO. Each UTXO is bound to a bitcoin address. To create a signature that is valid for this address, you need to know the private key that will be used to derive / create that address.
So a miner has no privileged position to spend coins that are not his own, since he does not know the private keys of everyone else. Regardless of what a court dictates, the miner can not spend any coins he does not own. Any attempt to do so would easily be identified as cryptographically invalid.
A miner might start making blocks that move arbitrary coins to the miner's choice, but those transactions and blocks would be rejected by the rest of the knot network, so that would have no impact on the network. The miner who creates these fraudulent transactions is simply ignored.
Each network node is a single instance of the code that independently checks the status of the network. Even if everyone Miner started breaking the rules, the nodes just ignored them (and we would expect some miners to surrender at some point and break down valid blocks again, as they would make a profit and otherwise lose money by removing invalid and useless blocks).