I can't find the thread anymore, but one user suggested to remove to ability of (low-ranked) members to make locked threads in the marketplace section.
I think this would go a long way to prevent the autobuy scams that a lot of Jr/Newbie members are pulling off.

https://bitcointalk.org/index.php?topic=1353400.0

Aren't these already a thing? See bill's profile, https://bitcointalk.org/index.php?action=profile;u=370611