Quote Originally Posted by RicaRuin View Post
They don't have an invulnerability because Hunts/S-Ranks were never intended to be community content that has everyone wait for it. The wait time and etiquette is something the community put in place, so from SE's PoV, it's working as intended.
I short invulnerability window wouldn't really harm to be fair. It wouldn't stop someone from ninja pulling the moment it ended but it would at least give a window for people to group up and get there. Blizzard did a similar thing to the Sha of Anger world boss in World of Warcraft. It's still farmed by some players to this day for it's low drop chance mount drop but the content is also so old that it dies within seconds. They added a small invulnerability on spawn/respawn so people could actually get it tagged rather than missing the kill. Sure, you can still miss a kill, but you get a small window that doesn't leave people waiting for ages after it spawns but reduces the change to miss out.