> a distinction may need to be made between flags and banners.
I tried to find a clear cut definition, but couldn't. In my book, if it is more than twice as long as it is high, it is a banner, not a flag. Example: 6ft high and 9ft long (the most common 2:3 ratio) = flag. 10 ft high and 10 ft long (like the flag of Switzerland) = flag. 3 ft high and 7 ft long (exceeding the max 1:2 ratio) = banner.
> how do we keep track of what has already been posted and what may be a duplicate?
I'd volunteer to create a list and keep it up to date in the "additional information". I've been a professional pea counter all my life, this is going to be fun :-)