Moving minecarts or boats collide with players or mobs even if the collisionRule of the minecart's or boat's team prevents collision. It only disables pushing a stationary minecart or boat.
- Create a team
- Set the collisionRule option to for example never
- Place a minecart on powered rails which will later move the minecart towards you (for example as seen in the screenshot)
- Make the minecart and yourself join the team
- Make the minecart move towards you
→ You will see that the minecarts stops in front of you, but you cannot push it
Based on 1.11.2 decompiled using MCP 9.35 rc1
The methods of boats and minecarts overriding net.minecraft.entity.Entity.getCollisionBox(Entity) do not test if the entity they are returning a bounding box for, can be collided with.