(Review requested)

Adding a fictitious vertical separation to get rid of a warning generated by the iD editor is not a good idea.

The iD editor makes a lot of suggestions, some of which are ill-advised, but they are only suggestions. If you do not know how to resolve an issue, even after reading the documentation, please leave a fixme tag on the affected objects and/or add a note to the map.

The actual reason for iD generating this warning is that you incorrectly added building=yes to the enclosing polygon for the school in changeset #159150764. If this really were the case, iD would expect to find different layers, or a tunnel=building_passage.

I have fixed both issues.