I agree that group interaction was not the focus of the article, but the parent comment seemed more general.  Also, to a lesser degree, I think this unfortunate social rule applies in person-to-person interaction.  "Why did you not bother to object yesterday when I told you of our group's plans?"<p>In more informal social situations, I don't think this odd social rule is an issue though.  After all, if I start talking to somebody at Starbucks about his laptop, it's hard for him to later claim I had an obligation to help him choose the right wireless dongle -- even if he mis-stated his needs for G vs. N connectivity.