I don't think it came up when I was DMing, but of course I would tell the player whether that would stop the hit or whether he'd waste the power. It's the same with telling which monster is a minion, or whether a monster is rather tough, agile, or strong-willed (i.e. which NAD would be high/low).
If I need to make fights tougher I can just make them tougher directly by adding more / stronger / smarter monsters, I don't need to screw people over to "win" as DM.
(Win in "" because the real DM Win is a challenging fight and a fun evening for everyone, not dead PCs)
If I need to make fights tougher I can just make them tougher directly by adding more / stronger / smarter monsters, I don't need to screw people over to "win" as DM.
(Win in "" because the real DM Win is a challenging fight and a fun evening for everyone, not dead PCs)