If I was those people I'd buy BTC from these little markets (Coinbase, Bitstamp & others) then sell for a 2x profit on OTCmarkets.
The catch is that you must give the bitcoins to Grayscale, they will give you fresh BIT shares, and you must keep them for 1 year before you can sell them on the OTCQX market. Good luck...
If this is true, then it explains a lot, regarding the difference from the exchanges. Do you have any source about this info? I constantly kept scratching my head why this is happening...