Sorry but last sentence when you write about "weeding out":

• There will always be new scammers
• There will always be new victims

The best way to mitigate against fraud is intrinsic mechanisms such as:

• Bad listing of wallets: cannot send to and cannot received from.
• Labeling of coins: coins that have gone into a bad wallet will be labelled unless they go into a good wallet first to remove the bad label.

Things like who gets to label a wallet bad and who gets to own the good wallets and how will that work decentralised: i think there is alot of smart people to do this, but I do not see how this is any different from a couple of companies with proven honesty records (say the likes of Standard & Poors, Moodies: but those are corrupt in core and substance) doing the labelling.