I haven't experienced it myself, but with two reports in this thread, I find this reliable enough to do a more visible warning to everyone.

Scammers are currently targetting users of this forum, stating that they've erroneously reported your account for fraud and that your account is going to be suspended as a result. You have to submit an appeal, ... and submit proof via Discord that you have committed no fraud.

This is a pure scam, attempting to get your personal information. The purposes for which they want this are unclear, but account take-over or directed phishing for higher value targets both sound plausible. As soon as you get this PM, block the user, and report them to GOG support. Do NOT join the Discord you're directed to. Do NOT tell them any personal information.

If you have fallen for the scam already, take it as a learning opportunity, but do not feel bad about yourself. These are trained criminals, who keep improving their script, and you're far from alone in not being on your guard enough.
Do immediately:
- change your password if you've told them that
- enable two factor authentication if you haven't yet
- change the email address associated with your account if you can
- report that this happened (including what information you shared) to GOG support so they won't hand over your account to someone with all your personal information who says they lost their password/email
- be on the lookout for further scams, targetting you through email / phone, where they tell you some of the information you shared, as part of proving that they are who they say they are. (E.g. "your bank" calling you out of the blue.)

And this is why I'm glad GOG enabled 2FA, but boy is it not a good day for their PR department when you have to break out the, "This is the exact way we're going to contact you" chart.

Is this something similar to the well known Steam scam?

After 'reporting' user with attaching fake screenshots and victims profile page (gotten with some scraping tool), the victim usually gets a message from the 'support'.

There is another way you can understand this is a scam. Because always the accuser has to firstly prove that the accused person is guilty. It is his burder/duty to do so, being the accuser. THEN comes the right/duty of the accused to prove his innocence (to prove that he is not guilty). Asking firstly to the accused to prove his innocence, is a sign of scam and a sign that you really haven't got anything concrete against him.

Thanks for the warning. I saw last night Catventurer's thread and I was really surprised but I never thought it could be a scam to be fair. They can potentially think about prevention of this by making the new users not being able to send PMs for example if they have not posted anything on the forums or bought something even on GOG. And while talking about scams perconally I've been always worried that one day these e-mails gog send with the promotional discounts may get targeted somehow. Usually the discount code is visible in them but its faster to click on the redeem link which could be the potential target. I am always careful with these before I open them.

Sadly this is not how it works with companies.

I got wrongly accused of copyright violation by some copyright troll, and my hosting provider at the time (Hetzner, never give them a single cent) imposed that I take down my websites… without ever asking for anything to back up the bogus copyright violation claim.

Obvious scam is obvious.
Why would a USER tell you that YOU need to actively contact support and the means by which to contact them?

How would you react, if some random dude on the street told you "Hey FYI, I reported you to the police for tax evasion by accident and now they won't let me take it back. They told me to tell you to call the tax evasion police at this tax evasion police telephone number which is totally 100% legit trust me bro and give them all your bank account credentials for totally 100% legit reasons trust me bro."

You'd be hard pressed to find more red flags at a chinese party rally...

There's a screenshot in the other thread that shows how they spin this, namely GOG being a faceless corporation with strict procedures, which customer support can't deviate from - and due to the "type" of abuse report, their purported process would be that GOG wouldn't "notify" the accused party themselves.

It doesn't make sense when you think about it, but by the time the victim gets to that point in the script, they're already panicking about losing their account, and not being given the time to think clearly about it all.

Yeah, these kind of mal intentions work by taking advantage of emotions rather than cold logic. The 'hold up, this looks like a scam' point of view requires a calm state of mind, which most of us can afford to have because we're observers with nothing at risk.
When directly involved, solving the immediate threat becomes a priority over taking the time to understand the overall situation and possible hidden schemes.

Hey Firek, can I ask you to sticky this thread? It'll be on page 2 in a few hours and this is important enough to stay on top. Thanks for the update!

How might you react if that person was some random dude dressed in a police uniform, claiming to be a policeman and stating that someone reported you to the police for tax evasion?
People tend to have an instinctive response to want to defend themselves and provide evidence to prove their innocence, especially so if it has come from a position of authority or credibility. Yet people 'still fall for the obvious scam' and end up incriminating themselves or doing something they shouldn't. If the police had such evidence, they would arrest you outright.
To say that it is an obvious scam is true yet seems quite degrading, when we are all susceptible to some version of it, if the story is given the right spin and attacks us at opportune moments.

A user added me
Username：BouncingBaby
BouncingBaby:hello! are you busy? I need to tell you something very important :3
He sent me a message, but I didn't reply.

I suggest to add a link to the report form to the first post:
https://support.gog.com/hc/en-us/requests/new?product=gog&form=report