I started ganking on my nightblade recently and I find it to be a good playstyle for short sessions. However, quite often, and especially during this event I find that most people die in a single combo or within 3-4 seconds very easily. It's clear that most of them are PvE'rs, and there is no denying that some of these players give you good Telvar (which is the main reason why most people run Imperial City anyway). At times even players with 30+ alliance rank die in a single combo, and similarly there are low ranked players who give a good fight.
So my question to fellow players who gank is this: Do you guys follow any rules as such? How do you draw a line between ganking and griefing?
Personally I never gank a helpless player twice.