When a power has an effect that occurs upon hitting a
target—or reducing a target to 0 hit points—the power
functions only when the target in question is a meaningful
threat. Characters can gain no benefit from
carrying a sack of rats in hopes of healing their allies
by hitting the rats.
One could argue that the attack is being attempted against perfectly meaningful targets (such as in the case of Mantle of Glory), but it is only the attack itself that is not meaningful. Ergo, you avoid the Bag-of-Rats rule.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.