Not true, RSLQ... if you look inside your "squads" folder, you'll notice that all the squad art in there is labeled by players' names. The noseart does not belong to a specific squad; it belongs to whoever started that squad.
So if the same player starts a couple of different squads (using the same ID), he will only have 1 noseart for both.
You can change your artwork between events, but it takes a few days for approval.