A post from Valve discusses "positive review bombs." This concept emerged after Ubisoft's Assassin's Creed Unity giveaway and donation after the fire at the Notre-Dame de Paris cathedral. The post is extremely lengthy and also includes a FAQ, as they explore the conflict this has with their stance on negative review bombing. In the end they decide to allow the positive reviews to stand, even if they are not strictly driven by the merits of the game. Here's a bit of the conclusion:

In this case, the Notre Dame tragedy has made it so that AC:Unity happens to now include the world's best virtual recreation of the undamaged monument. That's a context change that could be increasing the value players are getting from the game, so perhaps the game really is better than it was before? Or maybe that's unrelated, and it's actually players feeling good about Ubisoft's significant donation to rebuilding the monument? Irrespective of the reason, perhaps this is a short-term temporal effect? Should temporal effects even be included in Review Scores? If a game was heavily focused on a time of the year, like Christmas, we suspect we'd see it have Review Score fluctuations around Christmas-time, as more people bought it and thought it was better on average than people who bought it at other times of the year.

If visiting the virtual Notre Dame is a reason players have reviewing the game more positively, we'd expect the Review Score to continue to reflect it in the future, albeit at a lower volume. But that's still the case even if it's not the reason - the future Review Score would revert to where it was prior to this event.

So, we're not really sure what to do here. It doesn't actually seem to be a review bomb in the way we've previously defined them, but maybe that's just our definition being wrong. But even if we define it as one, we're not sure whether it should be off-topic or not. The overall Review Score would decrease by 1.3% if we marked it, which wouldn't have any significant effect on its visibility in the store (see the FAQ below for more on that). So either way, the game itself wouldn't be affected by our decision.

As a result, we've decided we're just going to leave it alone. But hopefully, this post has helped you understand that thinking behind why we've ended up there. If you have any thoughts on how we should approach this case, or similar cases in the future, we'd love to hear from you in the comments below.