Someone who does that doesn't sign up with one account. I'm sure if this is a scam he has multiple accounts that he rotates through. I tend to agree though that selling face to face / cash in hand is better for the seller, but could also be riskier for the buyer.
Like I said above, the secondary market is not an official regulated market. Just like how you can't go to the cops and complain that your weed dealer shorted you on your purchase, the secondary market all comes down to trust and risk aversion/tolerance. Stubhub will provides the frameworks and mechanisms to help resolve issues for sellers, but I doubt they go the extra mile given that it's the buyers that make their business model work.
Also, thanks again for the tic jaysblue! I had an awesome time, albeit sad in the end. I fully regret not going to Game 5 right now and 'saving my money' for WS tickets given I probably have no shot at them during the public sale.