Sorry I was just guessing, don't know anything about fingerprint powder. Plus, why would they fingerprint a poster hanging on the wall when there's no obvious reason.
I'm with IzzyBlanche, it's dust, and with Mirv22, the reporter was trying to be dramatic.
I watched the video and I don't think it's glass. It looks like acrylic and they scratch very easily. ( especially from moving) Acrylic is pretty common with poster frames