I expect it's case-by-case and done by repeat offenses rather than straight up.

Coming from somebody who's moderated forums for years. Getting reports is helpful and I've seen posts reported for things they've not been involved in and that is helpful too - it brings attention to the post and I can make a decision or discuss with other mods. When it comes to the user, it generally takes something bad enough to get kicked, banned or disciplined some way. If moderate or minor, we may step in and assert they're doing something they shouldn't at the first instance, but if it keeps propping up then we start making actions. But on forums I've moderated there's usually a thread in a moderator section for people who misbehave so we have a history, so we can see if they repeat and on one forum we could leave hidden notes on people's profiles. So I strongly suspect the GM's keep a log of what people get reported for and communicate with each other. So a report may not result in something being done, it depends on the severity, but may help contribute.