Oh, I just found this tidbit in Oatmeal's posting
"I simply treat the online board as a notation device and play the game on my board"
So even in justification, he admits having a physcial board violates the rule of having no notes.
If that excuse had been offered, I would have forfeited his present game and if happened again, would have thrown him out of the tournament.
Yes - it is cheating to use ANY notes during play. Notes can include anything that is written, a diagram or a board set-up with ANY position. If it was legal to do so in tournament, wouldn't you see everyone doing in OTB tournaments?
The problem is that your mind might be able to see a position better with a physical board that on a computer screen. You can also come back to the board when analyzing. In a sense you are using the physical board as a bookmark. Which is a note to aid your analysis. And that is not allowed.
I used to be a tournament director. I'm proud to say I never had a decision overturned ;)