
Zwordsman |
So circumstance bonuses do stack. but not from the same source.
So. It kind of depends on the GM. Is the source the action of harrying fire. or is the source the charcter doing said action?
Off hand I'm of the belief it would stack for the +4 myself.
Harrying is not an attack at the target. So harrying fire (or covering roll for that matter) would not gain the benefit of the harrying circ bonus either.
So I'm fine with the idea of a whole team harrying fire vs the main target to open up the main attacker's attack.

Metaphysician |
Hmm. If you allow harrying fire to stack endlessly, that certainly would explain how vast hoards of enemies could be threatening. 30 arbitrarily weak enemies vs one target, 29 of them use Harrying Fire, the 30th of them benefits from something north of +30 to hit. Which will run out first, the target's HP or the hoard's numbers?
( Admittedly, if its thirty CR 1/2 conscript mooks vs one level 10 PC, the answer is probably "the hoard dies first", but still. )