sealed homebrew games are for gays.
I think it's fine for homebrew games to ship unsealed, but opening a new game is still cool. It would be a nice touch for new Turbo/PCE games to come sealed, even in just shrinkwrap, with a gold SUPER CD logo, like some CD2 games had.
You could also have some stickers professionally printed pretty cheap, that have some sort of anti-game grading message or something. So that if anyone tries to have them graded, they would have to preserve the anti-VGA message, since the game would not be truly complete without it or the seal it's attached to. If anyone did go through with it and the VGA or whoever actually graded it, a buyer dumb enough to buy a gouged graded homebrew game would always have a little note on the front saying "you're an idiot".
You could also have a sticker simply giving the url of where to officially buy the game with the retail price. Gougers would have to try selling it without a photo or unsealed.