At first I thought the terrorist (or whoever) that chucked a grenade at Bush was being stupid. But on second thought, just the fact that he (she?) got that far will inspire insurgents. And if the thing had exploded, my goodness that would have been symbolic (even if Bush didn't get a scratch). I bet the Secret Service got taken out to the woodshed.
(Of course, I'm always dead wrong on this stuff. For all I know the SS itself chucked the grenade to build sympathy for Bush.)