I actually a few minutes ago added a check to see if the report thread has had the [SOLVED] prefix added, and this information is then displayed to all users who have reported the post to let them know the reporting of that post has been marked as resolved by the staff. I have not made this ready for release yet as I want to give the option in the settings to choose the prefixid that is used to mark threads as resolved.
Limiting users to a certain number of reports per unit of time would be trickier, but is something I will consider.