This is really quite simple. When it comes to today's normal situation -- two fit parents, without so much as an allegation, much less proof, of child abuse or neglect by either -- then BIC is a hopelessly vague legal standard. There's really very little need to argue the point because it's almost impossible for the opposing side even to make a credible rebuttal.
In our nation we don't diminish people's fundamental rights on the basis of legal standards that are so vague that a person of average intelligence can't guide his behavior so as to avoid the diminishment.
BIC as a legal standard is one of many serious problems with the current system. Many people recognize that. The system is fixable and we're working on it.
