I'm glad somebody started this thread, as it's something I've given some thought to lately. I have my own opinion on the subject, but I don't think the issue can be resolved without a bit of historical sleuthing. I'm not convinced it can be resolved, even with a bit of historical sleuthing. All I'll say is that the standard Hannay tartan, reputedly worn by a male of the name sometime between 1788 and 1844, is a primarily white tartan.

By the way, would the shepherd's check/Northumberland tartan be considered a dress tartan?