I've never paid much attention to the "safely remove" stuff and I never had much of a problem, USBs are hot-swap-able regardless and do not get damaged, the only thing "Safely remove" does, as far as I know, is assure that its not currently in use when you pull it out.
to answer your question tho, I don't know.
Friendly advise: get ready to lose your documents any random day.
Don't *EVER* do that!!!! the "safely remove" (as the other have said) unmounts the filesystems and flush the information that was to be written to the device.
As for the OP... it probably is just the energy supply :)