Is there a mechanism that counts the total number of flags raised by each user, and calculates the percentage of those flags that get rejected? If not, may we have one?
If the rejection number is too high — say, ten flags rejected in a day, 25 rejected in a week or 50 rejected in a month — the system should revoke the user's ability to cast more flags for a specific, pre-determined period of time, or even forever.
This would help moderators because they wouldn't have to review as many spammy flags — in other words, flags that are themselves spam, not to be confused with flags reporting spam posts — or as many instances of users getting flagged for no good reason.