bind (key) say "Stop right there!"
Wrong example. A bind only accepts 1 string, which means the correct format for such a bind would've been:
bind (key) "say Stop right there!"
Anyways, I don't know out of my head what the F1-4 binds are default to, but they should be something like menu_context or whatever. If you are unsure, ask someone in-game to simply type: "bind F1" (So without anything after it) and it will print in console what that key is bound to, so he can tell you and you can set it it right using console.