All children pick their nose, it’s a given.  I remember picking my nose as a kid.  I remember classmates picking their nose and then wiping it under the table in grade 2.  I see other kids pick their nose - even adults pick their nose in hiding and just don’t admit it.  It’s a natural cleaning process and probably one of the easiest since the tools are readily available.  I think the teaching to walk away here is to make sure that Vanessa is picking discreetly and then disposing of the gold in an appropriate manner.