Since it is not uncommon with people feeling hurt that admins "deleted" their posts each time a new member get their post rated to sub-default, it would be a good idea to set the default settings on this forum to never filter.
If someone for some reason do not want to read sub-default posts, they can always change this on their own. I'm sure that if someone feels the need to filter something, they'll find the option. But I doubt as many people look for the filter setting when their post disappears, since many other forums simply delete posts.
Not like it is a big deal, but you'll have less members that are upset for nothing. And it seems like a site would value to have their members happy.