What Exact Law Did the Coldcard Thief Break?

Wildly hypothetical question, please do not downvote me to oblivion. I am not excusing anyone here, kinda playing the devil's advocate out of curiosity.

So, a guy tried some random keys (coming from a space of points, a space with a reduced dimension than the expected 256 bit entropy, but that's all very rhetorical and technical) with a computer and broadcast some transactions (basically, signatures) using the keys he discovered with his own computer. That is it at a basic level, right?

He did not use a wrench attack, did not break into someone's home to steal a paper with passwords, did not drug or interact with any victim to coerce a password out, did not send scam texts promising investment returns. He is just coding on his computer talking to the Blockchain.

So is that really...illegal? I mean hypothetically, if he is caught, and he hires the top law firm in the world, what charge would stick? So far as I can see, he is just playing a guess-the-number game with the Blockchain sitting in his basement.

And if we allow (to the extent the Bitcoin advocates and Libertarians have any capacity to allow) a government to prosecute him, then what kind of precedent does it set with regard to a state's power to prosecute someone purely for interacting with the Blockchain and trying signatures/key combinations?

Are we ready for a political regime (basically, the state machinery) to come in and tell everyone how exactly am I supposed to interact with the Blockchain, that takes precedence over whatever the consensus protocol allows?

EDIT:

Yes, from the comments I can get there are laws and charges depending on jurisdiction that would stick. But I am far more concerned about the precedent that can be set by penalising someone for interacting with the Blockchain (a system not owned by a bank or a specific corporation) in a way that is just something the community did not like.

It opens a door to the political class to co-opt and regulate/alter the Blockchain in a way they deem convenient to protect a status quo or their regime so that any interaction outside the politically approved norm can be considered...well, illegal. Welcome to Bitcoin 2.0, I guess, where there is a 100 page legal bill on what exactly a node runner can approve?

Worst, seems like in this case, the whole Bitcoin community will cheer at the prospect of crucifying the coldcard thief for justice, welcoming such a possibility.