Unmarking is a local action, simply transferring what Gmail servers thought was spam into your inbox because you personally disagree with their classification.
But "report as spam" is an instruction for Gmails servers to vote for always marking as spam, there appears to be no way to undo the "report as" function.
But it will take much more than a single mistake to have Gmail permanently mark the email address as spam, as above. It would take many people over several days, according to Google Groups. |