If you choose to take an easy kill, by shoving someone off into an inaccessible location feels like you have chosen to give up whatever they are carrying.
If there was a fight, with "Bad AI" which accidentally made loot inaccessible, that would be a design error.
An "Intentional" NPC Action which made their loot inaccessible (Jumps off a cliff to keep you from getting his Thingy) also feels perfectly fine (and massively frustrating).
An "Intentional" PC Action which made their loot inaccessible, was your choice.
