Up to the manufacturer at this point, Vermeer has it Bandit not.
I'm sure OHS is a state thing not Federal so there's inconsistencies between states.
If the machine is not fitted with it standard like Bandit then there's no troubles unless a law comes out telling everyone to fit one retrospective like they did with the "roll over protection bars" for tractors etc.
Yes, it is a PITA especially when you load with machinery as a bump doesn't take much. Also depending on the angle of the chute to the ground it can be bad when limbs/forks are going up hill. Like imagine when the driveway has a plateau then downhill and the chipper is sitting up the top and the branches really rub on that bar. Vermeer has a sensitivity button now, low or high, off is not an option but I'd prefer it.
Wait till you got a face full of crap trying to stuff it in the rollers on your own then the bloody light comes on and all stops. You have to let go of the load so it springs back out, go to the side, press the wretched button, then start again trying to stuff the shute. Trees that'll piss you off here doing that are, poinciana, fiddlewood, african tulip tree, pepper trees etc
Dont wear gloves, have a stick or rake handy, dont use your feet and have a bloody brain!
Lord help us what it will be like in 30 years time, ban the whole job!