Think about it. You don't have to add your blizz account when making a jsp account. So if someone is using a vpn all the time and always makes new accounts, no one could know who they are until they start scamming. Which if you noticed, by the time it's figured out, it's too late. Jsp can only do so much.
It's also pretty much irrelevent. Trade the way your supposed to and literally nearly every scam would fail. Only communicate through Jsp, either make the other person go first if you know you're not going to scam someone, or use a med. That would remove like 90%+ of scams if people followed those super simple rules.
Looks like there's the solution. Add blizzard account section on jsp. Not only does it create a solution for people just jumping accounts and continuously steeling but it adds a level of confirmation for who you're dealing with in games. Basically, negates the need to announce who you are as you enter a game.
Additionally, "trade the way you're supposed to" was accomplished. when dealing with a scammer you will either lose the item or the fg. There is no way to avoid it if they want to. This person build the account for 5 months with 162 posts/trades. Lining up the previous time their blizzard account was referenced in the scam thread they only steal HRs at beginning of ladder seasons then make new accounts.
Having people add a blizzard tag to jsp account is the only way to stop this level of dedication to scamming people.