Forgive me but guarding the throttles seems to be a (no brainier) unless you are operating an aircraft that requires an unusual amount of force on the pitch or roll axis (do not know any to this spec.)
I did watch a captain argue with the landing f/o from G/S cap down to about 400ft agl to the point that that said capt slapped the FO's hand on the guarded throttle over this procedure.
Type was MD-11 and given the aircraft's landing charistic I felt the the F/O was more competent than the capt. by doing so.
I would also feel that unless the landing pilot flying any aircraft that could not be handled with a single hand (really how long does it take to to move the throttle hand to the yolk in a failed approach "TOGA" being the first response) that could not be done so responsibly is ridiculous.
I do not see how even by my uneducated (formally) view is not logical.