I'll maybe act like devil's advocat but sometimes it is necessary to pull when a decent amount of ppl arrived in front of the boss. Why ? Simply because when we wait too long the amount of ppl in the same area is exceeding server capacity and most of the hunters get a D/C mark over their head leading to disconnect and most fail to get a reward even if they were the very first persons to be in front of the boss.
Such things happend many times.
But well, i don't see the point to witch hunt the ninja pullers, hunt monsters are always respawning after a while, it's not like you'll never be able to kill one again if you miss it once... And if you track timers properly you can easily be in time to 70% of the A ranks at the moment they are getting found.