Of course there are implicit expectations and etiquette. What I’m saying is that corporations are less likely than individuals to follow them so if one doesn’t

Of course there are implicit expectations and etiquette. What I’m saying is that corporations are less likely than individuals to follow them so if one doesn’t want to be screwed they have the opportunity to do it with the license. You speak of academic code, and precisely some projects require (or at least ask for) citations in their license file if use in a research context.