damn, that's is messed up. never heard of a fan flying apart like that. they can't be making products that are downright dangerous like that
i've rubbed my fingers a couple times here and there, but never against a larger or high-speed fans, mostly generic (all but 1 fan in my case right now is all properly guarded up).
the dumbest one tho i ever did, i just about had a fanblade permanently embedded in my face. i was a few years ago, i was using a panaflo 120mm to cool hdd's, it was hanging out the front of my case (taking up 3 drive bays). well, it was temporary, i was just seeing if i'd even like it. i had it held in with tape, and i was sitting there and the tape let go. the fan fell out and down, hit the desk, and one of the fan blades broke off, and i caught it good.
ah, to be young & dumb...
man, when i had my nidec 120 in the case tho, i didn't even put my fingers in there when it was running, screw that. it's the kind with 3 extra-sturdy blades, and has an unbelievable rotation speed. i would have lost a hand :/