We aren't supposed to derive benefit from melachot performed by other Jews on Shabbos. But what if it didn't happen this Shabbos?
What if our guest brought a bottle of liquor as a gift last Shabbos, and we understand he carried it outside an eiruv. This Shabbos, can we drink it? If we did, is the transgression equivalent to having drunk it last Shabbos?
What if the melacha happened many weeks (/months/years) ago?
Note: I understand that the obvious assumption is that the answer is "No, we can't drink it," but I am curious to see if this is authoritatively treated in a source.