Then maybe they at least have some pieces of Mars on them
Even if Phobos and Deimos weren't directly ejected from the Martian surface,
there may be Martian rocks from impacts on them, in far more pristine shape
than anything similar that landed on Earth - to say nothing of improved odds
for them having fragments of Mars over any other place in the Sol system.
Wouldn't that be something, to have Phobos-Grunt return to Earth with samples
of Phobos AND Mars, without having to land on the latter.
Hey, Opportunity's heatshield landed right next to an iron meteorite in the middle
of a desert.