We had a number of teams asked if balls under a goal count as ball inside a cube. At our past event we did not score those balls, was this the correct decision?
Pages 5 and 6 from the game manual describe how balls should be scored.
To be scored inside a cube, the ball must be partially or completely inside the cube.
When you say under a goal, do you mean under a platform where a green cube is on the platform? If so, it is hard to think of a circumstance where the ball could be at least inside the volume of a cube on that platform.