The second chiddush in lomdus R' Shachter quotes is cute. Why is it that in halacha (especially in Yoreh De'ah) we often have a base psak but then have kulos that allow for leniency b'sha'as ha'dechak? If the psak is 'assur', why should pressing need make any difference? R' Moshe Soloveitchik is quoted as saying that in terms of dinei yoreh de'ah, m'ikkar hadin the halacha is in accordance with the lenient opinion. However, we defer to the views of the stricter opinion because of the halacha demanding that we show kavod harav. One is not required to incur grave losses or be placed in an tenuous situation simply because of someone else's kavod, so in those cases we revert back to the base yoreh de'ah law and its leniency.
It strikes me that this approach suffers from the same weakness that the Ramban notes in the Rambam's reduction of all dinei derabbanan to the d'oraysa law of lo tasur - by doing so one has effectively obliterated the source to distinguish between different levels of chiyuvim. Every derabbanan issue should be paskened l’chumra because it relates to a d’oraysa issue. Here too, once we introduce the issue of kavod harav as a factor in practical psak, every issue should be paskened l’chumra because of kavod harav. How can one justify the right to pasken l'kula when faced with a safeik in a din derabbanan - the factor of kavod harav should always demand adherence to the stricter opinion? Why in fact should rov be a tool of hachra'ah - kavod harav should demand we respect the minority opinion even in place of the majority (assuming the views are not in direct conflict)?
R' Shachter himself suggests what I think is the more obvious approach here. Psak is not a definitive yes/no that determines right opinions from wrong - we consider all opinions theoretically valid, but must make some choice as to how practically to act. Where possible, we try to conduct ourselves so we satisfy most views, but where necessity interferes, we have a right to call on the validity of more lenient views to base our conduct upon. The GR"A's hachra'ah does relfect an absolute determination of certain opinions as right and others as wrong, but it seems quite a stretch to superimpose this approach on the Shulchan Aruch - one wonders why R' Moshe Soloveitchik did not opt for the more straightforward answer here.