Please add a note to the guideline page saying that all packages must correctly build with no network access. Something like:

Build time network access

Packages in the Fedora buildsystem are built in a mock chroot with no access to the internet. Packages should not depend or or use any network resources that they don't themselves create (ie, for tests). In no cases should source code be downloaded from any external sources, only from the lookaside cache and/or the Fedora git repository.