To be sure, it's a pretty loose contract and you could probably get away with printing a small amount of copyrighted material. But it at least shifts the liability onto the customer so the retailer can always point to the agreement and say "hey, they said they weren't printing anything illegally; that's on them for lying."
If you share the material with someone else, you're into infringement territory in most of the 1st World and substantially beyond, as far as I'm aware. If I tried to do this as a service, I'd probably get sued to the stone age, and I'd deserve it. But running it at home? Who's gonna know, and who's going to have a legal leg to stand on if they care?
Also we all used to joke about various parents doing this exact thing, and I don't think I've ever heard anyone get into trouble for it.
Isn't that what this post is about? They are planning to print a physical book made up of arbitrary text chosen by the user and then ship that book to the user.
So my conclusion is bunk, although the decision tree I loosely mapped out might still be useful for others so I'll leave it as is.
Can you share a citation for this? I'm a (former) lawyer and have never heard of a blanket protection for time and location shifting. It might be allowed for certain types of copyrighted content, or if done by the end-user. But I don't think there's a blanket allowance for all copyrighted materials, especially when a third party is involved.