The same way we can discard a splat book, asking by rules without Complete Arcane, for example, it's valid to ask questions stating "FAQ is IN" or "FAQ is OUT". The only autorithy on whats allowed and what's not is the DM, not even the player that asked the question. Here on RPG Exchange we are not on the roles of Masters nor Players - we are advisors, and we can only give suggestions to the people that come by. A player can check with us if "per the book" his idea works, but if his GM says "Not in my game", then it is out, regardless on what was said here.
We are dealing with games that use creative power and imagination, not with some legal stuff or programming languages. We need to understand that a book can't be more important than the enjoyment of the players and the DM. Asking "Raw only" just cuts out lot's of criativity.
No DM on it's senses will discard a good ideia just because it's not as "the book says". Almost all of the good RPG's call for the Rule Zero, giving complete powers for the players to create their game. We are dealing with a hobby on which people create, discard and change rules according with their tables. A House-Rule is not more or less "official" than any rule that the DM choses to use. "Officialness" is table-dependent.
Really, in the end doesn't matter what are the sources - a book, a homebrew or a FAQ. If the ideia solves someone's problem, then it did it's job. If the D&D FAQ explains something better than the Pathfinder FAQ, then why we don't recommend it?
If a DM closes himself from house-rules, for this or that, then this person must read the Dungeon's Master Guide all over again (or the equivalent book on other systems). If it is a player looking for some big loophole for power, that's not much far away from cheating.
Asking for a "by the book" anwser seens a bit wrong to me. Sometimes the books are not the best way around a problem. I think people should keep their minds open for insight, examples, and advice.