With reference to "bomber circuits" the problem often seems to be that pilots will insist on extending downwind from the point where they would normally turn base leg instead of turning base leg and conducting a Go Around from base leg maintaining circuit height. The aircraft behind this aircraft also extends downwind so that at many GA airfields most if not all the aircraft in the circuit are on base leg or final!!
By turning base leg and conducting a GA this means the aircraft behind you can conduct a "normal" circuit and quite often you can make an early turn downwind from the go around.
That said, there are times when you might extend downwind for sound airmanship reasons but broadly speaking my point is that aircraft should not extend downwind for separation purposes. Finally, these comments are related to airfields without an ATCU where we presume the expertise of the controller avoids this situations also!
No doubt, whatunion, will have some argument to rubbish what I have said in this posting - that's got that one off before we start!