Yes that would be considered griefing. If you didn't put any blocks down to replace them then they can be scanned, otherwise it might be to late by then.
"If ignorance is bliss, then knock the smile off my face."
—Zach de la Rocha
"People should not be afraid of their Governments. Governments should be afraid of their people." -V
I checked all the blocks in the area and all those that were destroyed were him. The sign that he included is just a slap in the face to both the Kataw and the server.