Can't speak for CO, but at DL we occasionally will get a bulletin informing us that buddy pass travel is embargoed and nonreving not recommended for a specific location(CUN, MEX, ATH). I don't think we've ever embargoed employee nonreving, but that might have happened a few months ago when we had to send a 777 to LOS to pick up a weeks worth of bags pulled for weight on the 763ER flights.

Anyway though, I've never seen all int'l nonrev travel from any gateway embargoed. I doubt that is the case at IAH, perhaps just the route to EZE is embargoed. I've been looking to go there, and EZE, GIG, GRU, SCL are all awful to try for right now, on DL anyway.

Good luck