I have seen the posts your talking about...several in fact. They click on "quote"...scroll down and click on "post" without adding any comments or remarks of their own.
I trust that FC will manage the issue as they see fit. We are expected to submit examples of our posts to prove that they are qualifying posts for the $3 credit. If there are members out there that do only a few posts to use in their examples they submit, then they are taking a big chance in whether they get the credit or not.
I understand your issue with "cheaters" and if FC likes your suggestion to create a thread where "cheaters" can be reported, and if FC wants the help of other members in tracking who makes legitimate posts according to the rules, I am sure they will do just that. I can see where reporting members suspected of cheating to create a red flag to help FC monitor this issue may be helpful, but that also opens up a door for other members to start wars with someone that they don't see eye to eye with or whatever. It is possible that those who are doing this just don't know how to use the system properly or are just not very skilled in the use of computers. Maybe they also have 30 legitimate posts in addition to the "cheating" or error posts they make.
My guess is that in addition to the 3 example posts we submit for the bonus they also read most of our other posts to verify we are following the rules and doing what is expected. There is a reason it takes so much time to get the credit...I bet it is because they are using that time to look at our posts to be sure they are valid.
Personally, my conscience would not allow me to submit for my bonus if any of those 30 posts were "cheating" posts. If I am going to take the time to do the work for the bonus, I want to be sure I get the credit.
Just my opinion.