How does this stop the scammer from closing his "blacklisted" account and then re-opening a new one? 

good suggestion Mr. docter but I do believe that this not a genuine case. this is just an extraordinary example of dumb people doing online transaction in the internet.

if people do little checking before deal, this all can be avoided.

does seller have been in lowyat long?
does seller have successful sales thread in garage sales?
does seller located in somewhere hard to reach?
does seller offer hard to resist deal?

BAM! conmen detected.

but NOO

erp derp take mah monneh!! I want iphone nao!!

The idea is good, but doesn't work in pm like what you mentioned just now, or they might give other bank account which is not barred previously.

p/s : Some of the seller here (including me) not really comfortable showing the whole account number to public as a step to prevent misuse from other party, so you guys can sensor and only display a few of the number and customer need to compare the "approved" account with the one that seller will provide privately in PM.

#Notification:

Only proceed to bank-in IF the account numbers are as below;

I am not talking bout LYN account as well.

If I were to scam someone, and my bank account is blacklisted, I could just go to the bank, close the account, and reopen a new account.

I will have a new bank account number with the same name. If you were to google my name, you'd not find my bank account number and thus you'd trust me base on this system, which in the end, LYN would be put to blame for providing a fake / flawed assurance system.