Well it's certainly not definitive that the "G" forces caused something to go awry in the amp.. But, just given the circumstances the most logical thing is that the jump caused the amp to stop,.. then you have to think what would cause this? Only things that come to mind are wires,.. be it ground, power, remote, etc in the Amp or headunit coming loose,.. or the impact causing an electronic failure.
There are tons of stories of people with Pioneer headunits hitting potholes, or speed bumps (something that shouldn't cause an issue) and their headunits suddenly stopping,.. and being "dead".
It just happened to me with some light to moderate palm hits on some panels on the side of the console.. which the same forces would have been generated in the shipping process. It may be something to do with when the internals are "hot" and getting the jolt verses not. Then again, maybe your amp is just fine (hopefully).. and you just need to trace down the issue.
My first inclination at this point would be to pull the amp out of the car and to test it independently to eliminate any uncertainty.