It may be an example of a different bias at play, specifically confirmation bias: they don't realize that the stones are being wasted and can't be retrieved. For example, chess masters commit confirmation bias less than weaker players.
(It's not that the players explicitly realize that there are better moves elsewhere but decide to keep playing the suboptimal moves anyway, because of sunk costs which would be sunk cost bias; it's that they don't think of what the opponent might do - which is closer to 'thoughtlessness'.)
I just finished the first draft of my essay, "Are Sunk Costs Fallacies?"; there is still material I need to go through, but the bulk of the material is now there. The formatting is too gnarly to post here, so I ask everyone's forgiveness in clicking through.
To summarize:
(If any of that seems unlikely or absurd to you, click through. I've worked very hard to provide multiple citations where possible, and fulltext for practically everything.)
I started this a while ago; but Luke/SIAI paid for much of the work, and that motivation plus academic library access made this essay more comprehensive than it would have been and finished months in advance.