I'm sorry but all you guys saying it's a douche move to flag up and interfer need to have your own faction look in the mirror first. I've only had one Galleon kill so far where we didn't have flagged Horde in the middle of the group trying to screw things up - and I've got a dozen kills on him between my toons.
Hypocrisy does not gain you sympathy. Man up, accept that both sides do this.
And this is expected, especially on PvP servers. Blizzard has said part of Galleon is to encourage world PvP so factions are intended to be fighting for control of him. Some players might not appreciate the competition - but it's all part of the game for world bosses now.
I help out if i see either side fighting a rare. Even if they are flagged. I made a druid pee himself i'm sure because i came flying down and started to kill the rare with him. As soon as it was over he was out of there like a bat out of heck.
My issue is when people force others to get flagged. I've had this happen too many times on a rp server. Want to do that crap? Go to a PVP realm. Let me quest and kill my rares in peace will you?
I'm actually the same way. I see someone fighting a rare, I stop to pitch in and help regardless of faction. Someone's pulled too many mobs? I'll help, red or not.
I've posted in the general forums a few times stating that PvP flagging on a PvE realm should be manual only, no autoflag on attack. Blizzard doesn't want PvE realms to be completely free of PvP risk, though, which is why it hasn't changed and most likely never will. At the core of the game, it's still Orcs vs. Humans. Blizzard doesn't want players to escape that - which is part of why the game is PvP themed for this expansion and players even have to do BGs as part of the legendary quest chain.