I'm not sure what you mean by "they don't." But you don't need guns for compliance. If can make it so that people will lose money if they don't follow the deal

I'm not sure what you mean by "they don't." But you don't need guns for compliance. If can make it so that people will lose money if they don't follow the deal, then no you don't need guns. People will comply because it's good for themselves. That's how compliance is enforced under a capitalist system and it's the main reason we live in a modern, golden age of cooperation rather than a medieval age of conflict.