This may sound stupid, but I got the achievement Sparring Rock Master without participating in the fight. I was farming some mobs in the area below the platform.
I’m not sure if I should be glad I got it (because I tried it and found it quite difficult), but I rather would achieve it on my own instead of getting it for doing nothing :-/
(The only idea I have why I got it: I revived a player who died from falling down. He headed back up there so I guess that’s why I got the achievement.)
http://gw2style.com/index.php – show your look and rate others – great filters!!