AMND Download Codes for Vinyl Shoppers

I've decided to take advantage of one of Bandcamp's latest feature additions, and have generated a few download codes for A Midsummer Nice Dream.

Anyone who buys a copy of the album on vinyl will receive a download code along with the album, so they may download a high-quality digital version of the release for their iPod, car, PC etc., at no extra cost. The codes are, as far as I can tell, good for one single download only, so choose your format wisely! mp3, flac, aac and ogg are all present and accounted for.

I haven't yet decided how to present the codes -- I could use stickers on the shrink-wrap, but risk buyers throwing this away with the packaging, or I could put paper slips in with the vinyl, and risk them being ignored at the bottom of the envelope. Could email them, but that's more work for me and could still be ignored. Hmm. Any preferences?