Colored armband for handlers

Sometimes, referee find it difficult to recognize the handlers quickly, especially for KidSize or during Drop-In games, this makes addressing the right person harder for referees.

A simple solution which would also look nice for the public would be to have handlers wearing a simple colored armband with the color of their team.

I don’t really see the point, because only the robot handler is supposed to be on the field and is not supposed to leave the field at any time… so I don’t really understand where the confusion comes from.
Also, what happens if a team comes without the armband? Would they not be allowed to have a robot handler then? How large would the armband need to be? What are acceptable colors? What if someone is wearing long sleeves that go over the armband?