Sorry Hillberg,
What we are talking about here (Cbox clutch) is the same on 212/412, so no advantage on the 212
As for the failure mode of a sprag clutch, it is non-engagement, not lock-up. If you have a clutch malfunction (don't like the word fail
) it will allow the Pt to go past the rotor RPM and other power section and you will get a weird split. At this point, the worst that can happen is sudden engagement which could 'snap' something... not a good situation
Good news is that this is an extremely rare occurence and you're probably better off practicing stuff that is likely to happen.