Nah, it's mainly about that one extra flag. The others don't matter that much, since you can't "cap/move" them...
Bombing run. It's about a ball, this is about a flag.
If you want to compare BR to anything, it's Fragball... or boomball I suppose ^_^
(ok, in essence it isn't that much of a difference)
If you'd call it "three flag ctf", people would probably think you need to cap 3 flags...
I wouldn't be surprised if they did.