Warner has never done inserts. All of their original releases were in snap cases or cardboard digipaks, neither of which lent themselves to inserts.
Thanks for the additional feedback. I will sort through all your comments at length later, but was curious about Warner never doing inserts. I suppose it depends on what you consider an insert? Releases like the 2-DVD "Batman Begins" and "Superman Returns" both have inserts...but they're just mail-in offers that are unrelated to the movie content. Likewise "Good Night and Good Luck" has a 1-sheet insert, but it's more a public service announcement. I thought the 2-DVD release of "A.I.", with a 4-page insert, disproved the rule, but on second look it is a Dreamworks (Spielberg) release, and only distributed by Warner?
The "Two Disk Special Edition" of "All The President's Men" (just picked up a cheap copy last night) did come completely bare.