LOL!!!
Dude, domination.
I bet he'll be mad when he figures out. Might want to get your AH transfers going.
You should send him a few more messages with innocent messages like "Found this, just thought i'de give this to the guild"
"Guild has helped me, just figured i'de give back to the people helping me!!"
Then if he does question you, you can just "What?! Dude, you saw those items i gave you. I'm just trying to help, i'de have no reason at all to scam the guild!"
Evidently the leader is dumb. He'll probably see this and just go "Oh yeah, i guess, why would he scam us, then send us items?"