A number of questions on tex.stackexchange have been met with the comment that "only a single question should be asked at a time". If this desideratum were in the FAQ, that would give the concept more weight as a requirement.
Since it's not possible for a moderator of a particular site to modify the "boiler plate" of the FAQ (see this question and this answer), the change would need to be made "higher up". Thus the request for this recommendation to be added to the FAQ "boiler plate".