I just see it as gathering intel, opposition research or what not.
If you don't want your signals hacked do like our intel agencies do. Have countermeasures in place. If they are hacking your voice coms use encryption etc.
If you are skilled at your craft and know you they are stealing your signals fill them with misinformation. If you steal their single telling you the next play will be a run and is turns out to be a pass you just got punked.
Its all part of the game.
I agree, as long as the opponent is breaking into your office or hacking your computer. It’s really your job to conceal your signs.
No, there are rules. He can’t pay your players. There used to be a rule against that, at any rate. You can’t give 200 players full scholarships. You can’t practice year round. You can’t pay off the officials. And you can’t scout opponents games in person. If you aren’t playing by the rules, you aren’t playing the game.