That may be so in a sense, unless the visitor has no means of making the call -- or does so poorly. I promise you that every robots.txt ignoring bot makes terrible judgments in that regard. (I'm not trying to overstate anything here; those that abide it make, on average, slightly less terrible judgments.)

But it's not just the visitor who gets to make judgment calls. The value of serving those pages is something the host can decide. Belligerent drunks who abuse the staff aren't allowed in the coffee shop, and if they do it often enough they're not allowed back in when they sober up either.