Boss Hunting Etiquette?

I was recently trying to complete the Quest called "The Desert Bounty" that requires the player to find and defeat Deo, the cactus boss. Deo spawns roughly every hour in the Royal Cactus Desert. After finding the location I waited a long while for the boss to show up someone else (clearly aware of when he would spawn) popped into the channel and killed the boss before I as much as nicked him. This left me pretty sour as I will have to wait another hour for a chance to complete my quest again without someone else sniping it in front of my eyes.

Now, I realize that part of this is on me for not having a character strong enough to kill the boss before the other person, but it really bites to have spent that much time of my day waiting around for the boss to spawn only to have someone else kill it even when I told them I was there for the quest.

I also realize that these bosses drop valuable items that the boss hunters clearly desire to make their own characters stronger, and they too would have to wait long for the boss to spawn.

What I am wondering, is there a community agreement around this practice? Is there a nice way to claim a channel when you are waiting for a boss without getting into a distasteful argument with the person moving channel to channel killing the boss forcing everyone else to wait?

Sincerely, a frustrated Mapler who just wants to finish his quests.