Epistemology in the Post Office

So I'm shipping many of my office books directly to my new office at Bucknell via the postal service's book rate (or "media rate"), since it's cheaper and in some ways easier. Well, not entirely easier: I walk in and announce my book-rate intentions and start schlepping the first round of five boxes or so. Since Laura and I enjoy our wine, several of the boxes are former wine boxes. The clerk notices the label and says: "Oh, that's a problem. That's a wine box; you can't ship books in a wine box."
me: "Why not?"
he: "Well, because we don't know that there's not wine in there."
me: "But you don't know that there isn't wine in the other boxes."
he: "But I'll ask you about what the contents of those are."
me: "Then ask me about the contents of this box and I'll tell you: 'it's just books!'" [Shaking box vigorously]: "Sounds like books, right? And anyway, can't you just open them up to check?"
he: "It doesn't matter: once we close them up again, other people will wonder."
. . . . and so on.

And even after patiently covering up all indications of wine and wine references ('vineyard', 'pinot noir', '750 ml', &c.), he insists that I cover up a large logo which happens to be a rooster. "Why? Am I not allowed to ship roosters either?" "No: it's that people will know that it's a wine box with that rooster on it." Right. . . . 'cause whenever I think 'rooster' I think wine. I'm not making any of this up. . . .

So apparently the mere suggestion that there might have once been wine (or roosters) in the boxes creates a salient enough skeptical scenario for the postal service which even direct inspection cannot resolve. Maybe wine bottles will grow in the box after it is sent: you never know! I was informed, however, that I could just cover up the wine labels and it wouldn't be a problem. . . . I'm skeptical. What about the shape of the box — the fact that its dimensions are roughly those of wine bottles arranged in a 3 x 4 grid?

Turns out that the postal service is also into fine distinctions about intentionality. In confirming the contents of the non-wine-box boxes, the clerk asked if there was any "writing" in the box. "Aside from the books," I ask? "Yeah, like handwriting," he responds. I admit that there's of course plenty of handwriting in the margins of the books. "Is it about the books?" he asks. "Because you can't send them if it's not." Wow. I'm afraid that there might be some borderline cases of "aboutness" in there (notes to myself to look at another book on a related topic, for example). Better let this go: "Yes: whatever writing is in the books is about the books."