Technically, the Moon wouldn’t become a new planet, under the IAU definition of a planet. Since its new orbit would cross Earth’s, it would be considered a dwarf planet like Pluto. This Earth-crossing orbit would lead to periodic unpredictable orbital perturbation. Eventually it would either be slingshotted into the Sun, ejected toward the outer solar system, or slammed into one of the planets—quite possibly ours. I think we can all agree that in this case, we’d deserve it.
