I do a lot of importing and find it VERY frustrating that a file can make it through Validation, but then be rejected on actual importing because the Import ID isn't unique. I would love it if the validation verified the import IDs of all files (Attributes, notes, etc.) so that this doesn't continue. (This usually happens when my Import IDs are too long and the last character is cut off and it costs me way too much time on large import files.)