Altsoba - what healer are you running with?

I know pally's can put a blessing (is it sacrifice) that transfers damage to them when you are hit.
They could use this if they know there are stealth (assume rogue) running around. One hit to you and the damage
will break the sap. Guess they'd want to drop that blessing quite quickly though to avoid too much damage to themselves.

other than that getting in combat would stop rogues being able to use sap, but that's an aggressive tactic.