First up, sorry RF i didn't mean to offend you.
The fact that the rotors separate and explode is something i am aware of
and have witnessed several times over the years with varying results.
Yes they are normally quite severe.

The hex in the centre pushes the magnets out as the loose outer rotates on the hex,
they have nowhere else to go.........
If you stop the outer rotating on the hex they stay in place as designed. This
is done by locking the two parts together. In the original setup, molten ally is
poured over the hex and the magnets to form the rotor. The ally is reliant on
the hex centre to stop it rotating. As long as the two parts are locked together
there is no problem.
The fix i use can only be carried out if the rotor is not really bad such as magnets
sticking out of the ally, but is quiet suitable for a slightly loose outer.
As i said it may not be for everyone to carry out the repair i have used but like
Stuart i don't see a problem with it.

The original rotor is a pretty crap design anyway but cheap.
Leon, if i was worried about criticism, i wouldn't have bought or ridden these
old crates for as long as i have.