As long as you keep paying me my full salary, and I keep accepting it, I won't work for anyone else. If you stop paying me, or I stop accepting the money, I can go work for anyone else I choose to.

If that happens to look like me sipping a pina colada on a beach in Bali while you're paying me to do nothing, so be it. You're paying my salary for me not to work for another company.

I think that's the only fair non-compete.