I think Mercatox are more a victim of losing management and/or support staff and exchange tech problems - they advertise having a huge backlog of tickets and i see wallets go up an down - some time after Jan 9th when many people were complaining of being unable to withdraw i was able to route my LTC -> BTC -> Dash and withdraw but i was concerned. This leads me to believe it is not a scam per se but a broken exchange with very little or no support staff. I would agree that with such a poor experience they should not be operating and would not transact any large amount or leave anything standing with them for long