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It looks like are confusing spammer with scammers here … In either case, reporting them is a community based service, free of charge, performed by any member of the forum.
Reporting spammers is for the most a silent action, performed by using the "report to moderator" on each post (see
[Guide] Reporting effectively for an overview on when and how to), and for the most, those reports are made without the need to post about it in the forum. I have make near to 1K reports (still short), and don’t recall having made a post about any individual case reported. On some occasions, there are initiatives that do make sense in terms of public posting, such as
CLUB]The SpamBusters! Keeping eye on the spammers for almost a year: [5.27.19]), in an effort to report mass spamming that follow a given pattern and that are tacked by more than one person at a time. Some of these initiatives may be merited, but that is not the driver to create them, nor do they really get merited since the objective is to help clean the forum, not gain merits.
Then there is the scammer side to things (which is what you indicate in the second part of your OP). Reporting scammers is yet another community volunteer task in order to help others from being scammed. Again it is, for the most, not done to gain merits, although some good catches may be merited at some point.
Neither task should be merit driven really, nor do they generally render merits as a result.