I didn't say you were a scammer but your actions certainly increase the risk hence the -1. You never disclosed this was purchased third hand or involved any third party online exchanges of MPs (dubious an totally unverifiable claim). So not only do you know the PIN code but so does the person you got it from and if they got it from an online exchange (care to share the link? ) then so does the person they got it from.
So even if you were legit the other two prior parties could dispute the MP resulting in a locked/frozen account or stolen funds.You didn't think that was relevant to include this fact?
maybe you should take a look at my history, I've successfully traded hundreds of bitcoins."
So have most scammers.
"Not to mention I encourage escrow. What kind of scammer would encourage that?"
Which does nothing if the MP is disputes days or weeks later unless you plan to allow the coins to be escrowed for months.