Release date is different from when the Rom gets dumped
Release date: when Nintendo officially allows stores to begin sales of the NDS game cartridge version of their games, and thus the first date that the public is legally allowed to own the game by purchasing it
Rom dump: when underground groups with the game cartridge take the game file off of the cartridge and upload it to the internet, illegally, allowing people with flashcards to download the game and play it for free, illegally. This can happen before or after the official release date.
Since Rom dumping is illegal and unofficial, calling Nintendo about it is both pointless and a bad idea. Nintendo doesn't do it themselves, they are in fact trying to stop it, so they won't know when it will happen for a specific game.