Not sure what Jesfa is thinking now, but I was under the impression that the populated sector rule only existed for populated systems at the time of the change, and wouldn't include sectors that have since had hidden system added and found. Otherwise we'd end up with sectors with just one system in it.
Okay, thanks Jesfa. Is there any way you could make that information known? The reason I ask is it will determine whether folks need to search their own currently-owned sectors to ensure they don't get any unwanted neighbors.