Conversation so far:
What is meant by the UKJ character?
created is a boy showing a middle finger and hiding a bottle of beer behind his back, wearing a blue baseball hat, a dirty white T-shirt, green Bermuda shorts.
What did the character represent?
he wanted to build up a bunch of other characters deriving from the other band's members or their friends.
Who designed the character?
UKJ Fan Artists or Mercer-Moish's fans such as Karaokeman .
What other characters were designed?
coverdesigns bootlegs to replace those which are disappointing (Goddamn Cool or As ugly as it gets for instance) or for old or new bootlegs without sleeves.
Where did the character appear?
Plenty of pictures of the UKJ are made for free for the UKJ fans.
Anything particularly interesting about the UKJ?
a warning message is always put on every bootleg about the consequences if that rule of 'NOT FOR SALE' would not be respected.

Question: What is the rule of "Not For Sale"?
Self-contained rewrite: What is the rule of "Not For Sale" for UKJ?