Personally I have never had any problems or complaints when dealing with Adol. (Sylvio or his brother) We have had 3 or 4 deals and they all went fine. I think Shawn merely places the words "adol collection piece" in the description of those pieces to simply convey to those interested a little bit of extra info or history about the item. I myself love finding out the "history" of games (whenever it is actually possible) merely out of curiosity.
I am also unsure if Adol sold his entire collection. He might have only liquidated part of it or certain items, etc. I will say though that after he "lost interest" in the neogeo, he did (has) become somewhat of a recluse. But then nothing stange about that. Alot of us (myself included) lose and gain interest in the neo (or any other games for that matter) from time to time. I also think that everyone has their "baby" (personal favorite system) and for him I think it was always (is still now?) the PC Engine (turbografx-16). Also he was heavy into Mega Drive stuff too. (Sega Genesis)
Billy