Let me check and see what iD is trying to warn about but from a practical standpoint, all admin boundaries are supposed to go on relations and the tagging should go there. I think the previous practice from older imports was to also include the tags on the imported ways, presumably because the tooling made it annoying/difficult to figure out what the way was for if it was untagged and only part of a relation.

I definitely don't want to cause every iD mapper a headache!