actually ANY open car on a track without a cage is in my opinion idiotic, we do track events to learn, when you learn you sometimes make a mistake, when you make a mistake you sometimes hit things, and when you hit things there is always the possibility of a rollover.........that being said, rollbars are for saving your ass when you screw up, it's not worth the risk to not have one with a cab.
my .02
ps.....nice welding