Is there a system in place to prevent new users asking, answering and accepting answers to each others' off-topic questions?

Question

Normally new users are not allowed to up-vote until they gain a bit of reputation by receiving up-votes or accepts from the community of a site. But this has a weak point that is being exploited:

A number of new users post, answer, and accept each others' off-topic questions before we can close them (in less than 5 min). Accepting each others' answers gains them enough reputation to start up-vote each others' posts.

We are closing them and the moderators clean up afterwards but this keeps happening over and over again and becoming frustrating to the extent that I think a systematic solution might be required. Is there a system to prevent this kind of circumvention of the reputation requirements using accepts by new users?

One possible solution might be to change the system so accepts from users who do not have enough reputation to up-vote do not give any reputation (at least until the answer gets an up-vote).

Answer 1

I think what they should do is make it so that whenever a post is closed and the owner has less than 50 reputation, the accepted answer is automatically unaccepted and the asker cannot reaccept it. Basically, what I mean is making "having accepted answers to closed questions that are closed" a privilege awarded at 50 or so reputation.

Answer 2

I do think all users should be delayed from accepting an answer for 15 minutes. IIRC there is already a day delay for self-answered accepts.

Perhaps after a certain reputation level it does become only a warning allowing really straightforward answers to be accepted after confirmation.

Answer 3

There are two moderation tools which are quite close to this task.

First is the suspicious-votes page. http://example.com/admin/show-suspicious-votes. It already shows when there's too many votes that a user had given to or received from another user.

Second is the show-user-votes page. http://example.com/admin/show-user-votes/123456. For a particular user it shows percentage of up/down/accept votes from and to other users. Suspicious mass-accepts can already be detected here.

What needs to be done: suspicious cases from show-user-votes page for each user should appear on the suspicious-votes page (or a similar one). There they would have to be manually revised by moderators. The reason is that not all cases of "mass-accepting" or even mutual "mass-accepting" are bad. E.g. 30% of my questions were answered by a single user and that's ok.

Possible signs for a suspicious mass-accepting:

• One of the following:

  • Most questions of user A have accepted answers given by user B (with total questions above 5)
  • Most answers of user B are given to questions of A and accepted (with total answers above 5)
• Accepting user or both have low reputation
• Extremely suspicious when they share the same IP.
• Accepted answer was given within a short time after the question was asked
• Question has received close votes