I might be missing something here.
All this talk of Alpha Prot is interesting, but "should" not be relevant to significant short term wind change at high altitude leading to underspeed or overspeed.
As in the OP's scenario of increasing tailwind, the SOPs are to descend as soon as sustained below GD and trending south with MAX THR. There should be no training of THR IDLE to counter Alpha floor. It shouldn't happen. Sure pilots should be able to recover from Alpha Floor, but that's nought to do with teaching underspeed SOPs, it shouldn't get that far.
Conversely, with sudden increasing headwind - as I alluded to above - there are three events I know of, make that 4 with Vilas' example above and I am sure many more - of an aircraft exceeding MMO due sheer and ending up in Alpha Floor. So a brief overspeed leads to the protections preventing a stall? Something is wrong there, and it all seems to stem from pulling THR LVRs to IDLE and in some cases pulling backstick to keep the speed below MMO.
In the overspeed situation, the 330/340 bird is tested structural integrity of Vdive of 0.93 and all aircraft are certified for short term excursions over Mmo. The wings will not fall off as soon as you go into the red.
SOPs say in the overspeed if the AP drops out (Vmo+15) fly manually. Leave the A/THR ON, select a lower speed and use speed brakes if required - even if the HSP activates giving a small pitch up.
From the FCTM - "ATHR engaged or setting manual thrust has the same effect on the overspeed recovery".
FCTM>
PR>AEP>MISC>OVERSPEED.
I make no comment on the crew concerned as it was 20 years ago and I don't know what was in the A340 FCOM then regarding overspeed recovery, but in the modern day context that example would suggest a mishandling of the overspeed by the A340 crew. Overspeed condition>THR LVR IDLE>Alpha Floor in <10 seconds. Not SOP.