Is joining a circuit any different to joining a (British) roundabout? The sensible option would be to respect the (runway-occupancy-compatible-) existing sequence and join intelligently, rather than to aggressively push in. At the worst just a small dog-leg behind may be necessary when joining from Crosswind to Downwind. Within a certain Class G Rule 45 ATZ not far from me this is often not the case when some thoughtless individuals fly straight-in approaches into a busy circuit, apparently oblivious to the spirit of Rule 12 and the consequent domino-effect disruption that such a manoeuvre will cause. Such situations are also not helped when 'condoned' by a mis-guided FISO.