Guild Wars 2

Never mind. Found this reddit post and it seems players within 1800 range are the ones scaling the bosses hp up or down
http://www.reddit.com/r/Guildwars2/comments/26vke4/boss_blitz_scaling_revelead/
So dead players apparently do count and it’s not combat based at all.

If this has changed in anyway I’d be grateful to know.

The boss may scale down immediately if you waypoint out, which is good to know, but they have always said that the game checks for activity and scales according to that. So people lying dead and not waypointing will get checked for activity and the boss scale down accordingly at that time.. He’s saying it’s faster if you waypoint, not that it doesn’t happen at all.