If they do this without giving (notable) notice, they deserve to be tarred and feathered for it on social media and in the press. It would be unacceptable behavior and the community should make clear that there will be punishment for any other park considering attempting it in the future.
If your coaster has a sudden catastrophic failure, that's one thing. That's understandable. If something out of your control is about to force the shutdown of a coaster on a short timeline and you can only give very brief notice, that's okay—we appreciate the effort. Knowingly shutting down a coaster on your own timeline and deliberately not telling anyone ahead of time is horrible. Even considering doing that for the world's tallest and fastest operating coaster is unconscionable.
It would be a horrendous sign for the new Six Flags' reign over Great Adventure (and really all of their parks, in general). It would betray a lack of care for the customer that would reflect very, very poorly on the corporation.