I actually find that green 7 quite intriguing. Every Pokémon game since D/P (and that's as far back as I bothered to check) has had an E rating (allowed for everyone). Could they be adding some action-filled cutscenes or other maturity that warrant a higher rating?That's right, something's missing, and I'm not talking about the green 7.
Or, maybe it's just a placeholder. In the ORAS announcement trailer, the game covers shown were tagged with "RP", which is ESRB's "Rating pending". These covers have PEGI ratings on them, and PEGI doesn't have such a placeholder. The American trailer also shows covers tagged "RP", so it suggests that the games haven't been rated yet.