Academics use footnotes as a guide to build on other peoples' work not (usually) as a means of verifying the accuracy of others' writings.

That's very true; so I guess footnotes aren't a good way of doing it for us - LW discussions are more akin to Wikipedia pages (where the references are supposed to allow the claims to be verified) than academic work.

So if footnotes won't do the trick, and personal authority obviously isn't workable, then what? The only suggestion I have is extensive quoting from the work in question. This allows one to find it later by googling and allows a more direct assessment of the quality, to say nothing of making the material accessible at all (I never can forget how much ancient philosophy - or ancient anything - we know only from quotations in other works).