I've sold a few modern Marvel comics recently, with no problems; some with the "peel to reveal" free code sticker intact, some without the sticker (code still useable), and some without the sticker but with the code used.
I've always specified which when selling, but have always been afraid to give it a "proper" grading. Would you mark down a comic from, say a NM to a VF+ for not having the sticker? Does it count as part of the comic? Does the code itself count as part of the comic, even though it expires?
In short: How are people grading their physically mint condition comics, with spent codes? Has anyone ie. CGC set up a precedence yet?