.... as the festival will get ebay to remove them as in this case!
Also, if you gonna try sell one because circumstances have changed and you can no longer go, it's not a fantastic idea to make them as traceable as this, as it may mean they can actually cancel them and prevent entry on the gate even if you are the legit ticket holder and have proof of id.
the muppet here showed their name in full, after covering up adress and ticket/reg number underneath, but also didn't cover the ticket number on the right handside of the ticket!

the text went on to say something about it wasn;t guaranteed to be for sale as his mate was going to ask again for time off work on the Tuesday - but auction was removed before then!
link to the cancelled auction
http://bit.ly/GlastoMuppet
This was first spotted for sale on Saturday, by Monday afternoon, even though it's a bank holiday weekend, the auction had been removed - and not the sort of removal notice that appears if people remove an auction by themselves!
Hope he does manage to get the time off, and hasn't had the ticket blacklisted!