Each difficulty must be able to be played by a single player. Thus, Multiplayer TAG-specific difficulties are not allowed since multiple people are required to play them. However, like CtB-specific difficulties, you may add an external link to a TAG difficulty in your map thread.
Any TAG Diff should be Unrankable. Since both players who play the TAG Diff need not to have a ranking system. Tag Diffs should be made just for fun and not for ranking competition. Besides, TAG diffs are widely known that it's not FCable and sometimes NOT passable without using HT/EC/NF Mod. So I highly recommend that TAG diffs/maps should be unrankable.Discuss.
Here are the negative descriptions of TAG maps when played ALONE:
1. You will never be able to FC tag since it mostly contain HIGH Jumps and Streams.
2. Inconsistent spacings which makes the notes hard-to-read.
3. MAJOR Decrease in your Acc if ever you have passed this song.
I don't actually see any reason why TAG maps should be approved at all since It is not really meant to be played by one player, but that's just me i guess.