Camping at a castle, fortress or other unreachable area is useless because the NPCs and players will kill the chest for sure. You, as the owner of a cursed weapon, MUST go and protect your chest, otherwise you'll lose it. The last 30 minutes guarantee pvp around the chests. Too bad it's not 2-3 hours earlier, many people will miss the best part of this update (IMHO).
I got one of the weapons yesterday on Naia and it was a lot of fun, but there were no big fish around, so let's see how it works out when they get involved. I guess it will be a shiet show as usual.