Piston can push NoGravity ArmorStand

According to MC-75197, Marker armor stands are still affected by physics and so should be able to be pushed. [Mod] Torabi also noted that the NoGravity tag should be used to prevent physics acting on the armor stand

[Mod] Torabi added a comment - 03/Sep/15 6:53 AM
Use the NoGravity tag if you don't want the armor stand to be affected by physics. That's what it's there for.

Pistons aren't gravity.

But neither is water and explosions. Water pushes it with force not gravity and explosions do as well. In zero gravity in real life, water or explosions shot at you would still move you, however the armor stand with NoGravity does not. I believe the intention of the NoGravity tag is to prevent physics from interacting on the stand rather than just gravity. Testing this with a shulker, the shulker does seem to move the nogravity armor stand at first, but no matter which direction, eventually the armor stand slingshots back into its original place suggesting that it shouldn't be being moved. Also, armor stands with NoGravity are not affected by Sweep Attacks either.

Also, armor stands with NoGravity are not affected by Sweep Attacks either.

Since you said that, they are affected by

/entitydata @e[type=ArmorStand] {Motion:[0.5]}

So they still can be moved.

Confirmed for 15w49b.

Reopened for Mojang to decide.

I can understand that "mere" NoGravity-AS should be able to be interfered with, as they are entities (albeit special ones), but MC-100398 should not happen:
Even if you set the Marker-tag to true, NoGravity-ArmorStands can be pushed from all directions.