I don't know if there have been similar cases with Sekai Project, just beware that Nekonyan can issue a DMCA at any time if they like. They've taken down translation projects like Amairo * Islenuts, KoiChoco for the PSP, and most notably Houkago no Cinderella after 2 years of work and two routes away from completion. The news of the takedown of this visual novel greatly saddened me and engraved my disdain for Nekonyan in my heart.