I really would not want to work over Mexico, unless it was a high area and single ship Instrument lesson. That way there is less chance of a mid air and I would have the ability to glide back to US airspace, if the engine quit. I would not want to punch over Mexico these days. We would need blood chits for the cartels, if we wanted to see the USA again. Besides now that UPT schedules are about 50% of what they were back in the day, we rarely run out of working areas.