GS/BS applies to everything subjective all the time across all stack exchanges and is one of our most frequently linked posts, to the point that we have a highly supported proposal to get a shortcut bracket link to it. It was my impression that the game-rec guidelines (specifically "You may only answer one of these questions if you have actually done it or seen it done, or if you have a detailed reference from someone who has done it (with details like how and results).") are and were intended to be strictly stricter than GS/BS advice, and furthermore to address answerers rather than querents, among a number of other major differences. I have recently been told by a mod (@mxyzplk) that these guidelines are, in fact, identical to the aforementioned famous post. I don't understand how this is the case. Is it? Could someone please compare and contrast them?
The article Good Subjective, Bad Subjective is targeted at questions. But it's advice provides an outline of what we want out of answers (i.e. The Back it Up! Principle).
Back It Up! means that your answers must be based on either:
Something that happened to you personally
Something you can back up with a reference
Both GS/BS and the game-req guidelines basically boil down to one thing: "speak from experience."
The trouble is, speaking from experience is more of a spectrum than a discrete point:
I've heard of a system, and it sounds like it might do what you want.
I've played a system, and I don't think you'll break it.
I read about someone doing something else with a system, so you can probably do your thing with this system.
I read about someone else doing something similar with a system.
I've done something similar with a system.
I've done exactly this with a system.
GS/BS doesn't do much to draw the line at where the tipping point is on the spectrum (because it was written towards question authors).
The game-rec guidelines apply GS/BS's guidelines in an answer-focused way. The idea being that our game-rec questions were getting crummy answers ("GURPS can do anything!"), and that the only way to "save" them was to improve answer quality.
So... The game recommendation guidelines are a codified, aggressively enforced, version of GS/BS. This means that they allow a smaller subset of answers through (relative to the site at large), but there isn't a specific set of rules that are "added" or "missing" from one or the other.
They are the same in all substantial points. The difference is in application: GS/BS is guidance for what makes good questions and good answers on a site with an inherently subjective topic, while the game-rec guidelines say “…and for recommendations they're not just suggestions, it's going to be enforced.”
The difference is in the “MUST” in the game-rec guidelines:
Answers MUST adhere to the "Back It Up!" principle
So yes, they're the same. The difference is that answers not adhering to GS/BS will get a finger wagging and downvotes, while answers not adhering to the game-rec guidelines will get a finger wagging, a pause to see if the wagging helped, and then deletion if not.