Is there no combat log event for Feign Death?
 

Note: I am using the classic wow beta client.

I am registering the "COMBAT_LOG_EVENT_UNFILTERED" event on my primary frame for my addon, and it seems like there is no event trigger for when I feign death. Does this seem right? Is there any way to recognize when a player uses feign death?

Doesn't Feign Death apply a buff on the hunter that casts it?

It's odd. It applies a buff, but AURA_APPLIED is not triggered. Even then, I still would have no way to identify when an enemy player or a player in a duel casts it with the classic client since UnitBuff will not work on them if they are not considered friendly.

Edit: Also to add onto this, it seems like eating/drinking does not trigger a combat log event either...

UnitBuff() and UnitDebuff() seem to be disabled in classic. UnitAura() still works with relatively limited functionality. Not sure if they removed the HARMFUL/HELPFUL filters that would break these functions or if something else is happening.

I'd imagine that it has always been a hidden spell/buff, as it is intended to be a convincing "death." Addons only know as much as the player if only more accurate, so a fake death should appear as real as possible to both. Of course they were kind enough to let you poke a dead body should they be faking.