Is it possible to have spoilers for a film that came out in 1954? Well, in case you haven't already seen what is probably in the top 5 most influential films of all time, spoilers ahead.
Like every other Kurosawa flick from the end of the war through maybe Yojimbo (and I'd be willing to consider an exception there too), Seven Samurai was foremost an allegory about the dysfunction in Japanese society that produced the Pyrrhic loss in 1945. Think of the last scene where Shimura looks over the village, half his fellows dead (including the brilliantly grotesque Toshiro Mifune) and remarks about how the miserly, miserable farmers were the victors in the conflict.
Now, this film was set prior to the establishment of the Tokugawa shogunate (and I think it was even before Nobunaga's campaigns), which means that in the film's universe, regional warlords kept their territories locked down pretty tightly. Stuck in a grim manorial autarky, everyone in the lower feudal ranks enjoyed a lousy menu of alternatives. No voice, no exit. In the film, the titular samurai were scrabbling for work that just wasn't available. You get the sense that they were on the verge of eating their own shoes (a pretty common theme in a lot of Japanese period drama, even in those films made after the economy had recovered), but even they weren't as bad off as the villagers, who in one memorable scene, set to picking individual grains of millet off the dirt floor to avoid starvation. There's no sense that the choice to contract unemployed swords-for-hire is anything but a last resort for the desperate villagers. The poverty of the samurai suggests that what we see is desperate bargaining, not disparate bargaining.
Seen as cinematic penance for 13 Dec, 1937 (and yes, I agree that Rashomon is the better vehicle for this particular apologia), the film encourages a viewer sensitive in EE matters to question if honor, duty, or some bowdlerized version of bushido is a tacit term of any contract proposal. I've mentioned before what Adam Smith had to say about the common duties of a morally complete human towards preventing the suffering of others. This sort of moral impetus is tough to capture in quantifiable measurements. But it sure exists. Tithing is a thing that people do.
So does this mechanism expand or contract the sphere of euvoluntary exchange? Or is it more contextual than that? Does honor or duty make it more or less challenging to adjudge ex post regret from afar? Watch this clip to refresh your memory and tell me if Shimura's character regrets helping the village.
Watch the clip and tell me if Japanese conscripts regretted serving under Hideki Tojo.
It ain't that easy, is it? Now strip the context from a supposedly regrettable exchange and make a big ol' ex ante claim about the regrettability [sic] of terms of trade when non-pecuniary motives are lumpy and heterogeneous. Practical rational choice theory gets a whole lot tougher, especially when filtered through the curious incentives faced by career bureaucrats.