AEM "Error: Only sealed (built) sub packages allowed"

I want to get rid of "/etc/tags" as the new place for tags is /content/cq:tags.

Our Adobe Rep wants us to do everything via packages ( i.e. no crx/de directly in prod).

I planned to build and download a package with filter "/etc" and remove /etc/tabs and rezip and ask Adobe to reinstall it.

But I can't build a package with filter "/etc". It gives the above error message. I believe it is because root level filters might produce too much output ?   I don't know how else I am going to get rid of /etc/tags with using packages only.

Any ideas?

thanks

Fiona