alot of users have been getting scammed by high ranking members due to the hack. passwords are changed and btc is scammed. anyway bitcointalk can place a negative on trust on any user when they change their password for a set period of time like 1 week. this should give enough time for a user to report the account compromised.
thoughts
I think It would be a waste of time to implement this feature , most of the recent account that got hacked are old (so old) that they didn't change their passwords for years ! (See their UID , It's probably so low compared to yours or mine) <= I'm speaking about the database dump that was being sold in the Darknet.
Other hacks that happens are targeted to specific users and It's the responsability of the account owner to protect his account , as for those who are getting scammed , It's also their responsibility to check the user trust , post history and do their investigation. Your Idea is to leave a negative trust for one week while the SecLog :
https://bitcointalk.org/seclog.php shows the changing passwords logs for the last 30 days !