I was always under the impression it shouldn't be a problem to use the same site codes in different forests, but:
We have a prod forest and a new lab. They are in the same network, DNS wise, but there is no trust between them, I can just connect to any system in both ways. Now I see prod. clients popping up in the lab, although they don't seem to get assigned, they just show up in the collection and still belong to prod. Don't have more information than that, but do I have a problem? If so, I guess, I have to re-do everything with new site codes. If not, why is that and how to prevent this? I really thought that shouldn't be a problem, sigh.
