omg omg omg panda what?!

[protector]

If someone threatens to break an agreement, their word is void, and the dealbreak already happened.

Wrong. I could get LG to say some dumb **** and use that as a justification to dealbreak CR, but it wouldn't be justified.

If I make a deal with someone and then have to constantly worry about them breaking that deal, then their word is literally meaningless and the deal might as well have never existed.

That's your problem. The risk is always there, no matter what. It's best to just assume everyone sticks to their deals and deal with it if they don't. This usually works fine

If my company signs a contract to provide a service in exchange for money, and halfway through the other party says 'you know what, on second thought, we're not going to pay you unless you also provide this other service that wasn't even in our original contract', We're going to immediately stop work and call our lawyer. I'm not just going to happily continue providing services with no expectation of being paid.

You don't bluff breaking a contract. That's how you get your ass sued.

Same principle should apply to diplomacy in-game.

Don't compare a game with reality. You don't shoot someone IRL because they killed you in a game, right?

Because he posted logs on the forum Francis threatening to dealbreak them within three hours of their wave?

Threatening to =! doing
Threatening is dumb and as you said yourself, "call their bluff every time", i.e. see if they put words to deeds.