Without wishing to cast aspersions, it's probably better to write your forum name in on a scrap of paper (on in an application running on the device) before taking the photo. The idea is to make it difficult for someone else to replace your name with theirs, and fraudulently sell a device they don't own.
That said, I can't remember that scam ever being attempted here. Only one time when someone tried to sell ED a wholesale batch of Pandoras.