Board Thread:General Discussion/@comment-82.43.138.194-20140707202022/@comment-3250527-20141213081757

Crossovers are considered non-canon.

The SAO and AW timelines have a gap of at least 20 years, so the SAO/AW crossover was essentially a time-travel bug story.

Even so, there are titles (such as the WIP Cradle of the Moon side-story) that are considered unconnected to the main SAO timeline, even though the same characters with the same names with the same terminologies are used.