People are free to do this?

Change Distribution settings right before killing the boss?

 

If this were any other instance besides Infinity Shard, then yes. With Hyperion, each player gets their own loot, the boxes. Those cannot be taken by any other player besides yourself, so ninja looting isn't really possible. Even if he did change the loot to Captain only, after 4 minutes it becomes lootable by the entire Alliance, allowing you to get your stuff. Besides, it doesn't really look like he took anything important from your screenshot, he probably just didn't feel like waiting for all the members to loot and wanted to get it first. People can be impatient like that. If this happens to you on another instance, such as Rentus Base, take a screenshot like you did here and post it in In-Game Reports for the Staff to take action on.

Happy Gaming!

 

Thanks for that fast reply.. thought i can't loot with this.. thanks again