We have at least 50 questions about bags and what set they come from nowadays. But the skills required to determine the identity of an unmarked bag are not necessarily the same as those needed for piece-ID. I think that this is a big enough of a gap to constitute a new classification. Thoughts?
Personally I think set-identification would be better than "bag identification" - it would cover both "what set do these random pieces come from" and "what set did this unopened bag" come from - the skills required for both of those are the same.