ROB
I don't know if 'all' aerobatic aircraft are fitted with 'fail coarse' props, things like Bulldogs and Pitts' with Hartzell props certainly are. There are many 'composite' props out there and I presume these operate the same way.
The CSU works the opposite way round so you have to make sure you get the right one!
The easy way to tell is that at the blade root there are counterbalance weights which assist the blades to coarsen off if the oil pressure drops.
I have always presumed that this is to stop the prop from trying to unscrew itself from the front of the aircraft during manoeurvres that result in fluctuating oil supply.
The prop doesn't actually feather, it just goes very coarse (if that makes sense!).
Hope that helps!