In a competition, we were told that removing cubes from posts were illegal because when we removed them they would fall out of the field. Referees counted this as intentional removal of objects and we were given a warning, and we were unable to de-score any more objects.
Well, there’s G9 in the manual, but I suppose it might be open to interpretation. The part I highlighted below seems to suggest (to me, at least) that you could intentionally remove objects from the field so long as you are doing it during the removal of scored objects. But I’m no authority on this, so maybe you should post your question in the Official Q&A Forum. I know my kids pop the cubes off of the tops of posts all the time and cause them to fall out of the fields, and they’ve never been warned against it.
I would think that if it falls while removing it you are just trying to de-score and not intentionally trying to remove items from the field. But they say Judges have the final ruling.
The rules allow descoring and scoring to accidentally result in cubes leaving the field.
That is how every event I have seen and reffed has interpreted the rules. This is the same interpretation of that has been used in the last few years as teams knocked big balls off of goals in the past.