That was my understanding with the basic HPF tune, that if push came to shove I could simply plug in the "dongle" into the engine diagnostic port and reload the Ford OE tune that I have on my lap-top that would over-ride the HPF custom tune and I could then get it re-done later once I'm back at home. The alternative would be I guess to buy a second-hand engine ECU ahd have it ready to swap over should the need ever arise. It would simply have to be programmed to my vehicle's VIN number.
As I see it there is just as much of a chance of the standard Ford "tuned" ECU playing up in the middle of the desert as a customised one, unplugging a "plug and play" unit then wouldnt be any advantage at all, the ECU would still be in a limp mode.