I wouldn't really call this misconduct. Seems to me it came down to someone being nice and giving you what you wanted. If he won the shield then there is nothing stating a player has to be nice just because he can't use an item. Also, he could have had a friend or Ls mate that was a GLA and decided to give it to them.

I can understand your frustration because of this though. The guy was a jerk in the end and should have just said no instead of leading you to believe in a false trade agreement..