If we had a proper PM capability, tied with a FS/Trade section, that would cover all of this, as folks could trade,(via Paypal), without it becoming a big site management debacle.
I saw a hint that a PM section is in the works on another thread.
If they offered that up alongside a FS/Trade section, it would be da bom.
A disclaimer stating that personal sale/trade is entirely at the risk of the buyers, without personal sales being sponsored by, or the responsibility of Massdrop should cover legal ramifications.
Taking a page from how Headfi operates this would be beneficial, serve Massdrop well, I should think.
Big Up Thumb to the idea, hope this pans out.