That's an excellent question. My guess is that the PM would be less sensitive to overheating due to low fuel than a Chevy or Ford van. This is a returnless system, so unlike a Chevy the pump does not just run flat out all the time. The PM uses PWM (pulse width modulation) to pulse voltage to the fuel pump and thus vary the amount and pressure of the fuel the injectors see. This means that it isn't running all the time, so I conclude it should be less likely to overheat.
If it does, there is a hatch by the driver's seat that allows you to swap out the pump without having to drop the tank. So that's something.
All that said, I ran the PM out of gas once so far in ownership, and it didn't seem to hurt anything. But I see no good reason to push it further than when the low fuel light comes on at 50 miles of range.