How are they going to treat a parent holding the candy bag for a young child, and saying 'trick or treat' for or with them... Would said parent be in violation?

How are they going to treat a parent holding the candy bag for a young child, and saying 'trick or treat' for or with them... Would said parent be in violation? I have to wonder what their legal justification for this law is, and whether it will hold up if ever challenged. (doubtful) It seems on the surface to be wildly abusable, and to be infringing on the first amendment rights of everyone over 12 who wishes to dress up and visit their neighbors on Halloween.