as for this being dangers rubbish. - dont be such a wimp! have you never spun a plane!
Fixing to here real soon now, but I'm not going to load up in a Seminole (Twinstar, whatever) to do them...I'm going to get a Citabria (Champ, Decathlon, etc.) and spin it. Matter of fact, I have yet to fly a multiengine airplane that isn't placarded against intentional spins.
Furthermore, I don't know how to get out of a flat spin, which can (and does) develop as a result of failure to avoid stalling the airplane with one engine inoperative. I have a vested interest in remaining alive.
I'm a bit confused here - why would zero thrust be a problem cf flight idle ? - presuming that you are not talking about some oddball aircraft systems problem.
I don't think there's an aerodynamic problem, I misquoted the PTS.
Feathering the propeller (e.g. zero thrust) reduces Vmca.