The Guardians Sentinel skill that has a chance to proc stoneskin on a group member is not work at all on deathtoll in PVE or PVP. I've checked all combat log and ACT and it does nothing more than show up as a buff in the maintained window.
I have not verified this in PvP. But I am 100% sure that it works in PvE. I play a level 50 guardian.
