In the last day there has been two verified cases of Blizzard interfering in loot decisions made by a Master Looter.
In both cases, people were asked to roll on an item which was then given to a person who did not win the roll. Both cases had reasoning that was not discussed in game but was instead discussed on Discord.
Blizzard has said the following on loot distribution:
No one thus far has been able to provide me with a post or policy that indicates Blizzard will intervene in loot decisions, yet they’ve made plenty of posts implying that it’s up to the community to deal with “Loot Ninjas”.