In cases like these, if allegations turn out to be complete BS, does law enforcement take automatic action against the accuser? Or are people basically able to throw around false accusations, ruin a person's life, waste taxpayer dollars, and face no consequences themselves?
Again, it's important to point out that a charge not leading to conviction does not mean claims are B.S.
The criminal offense of 'public mischief' covers deliberately false police reports:
140 (1) Every one commits public mischief who, with intent to mislead, causes a peace officer to enter on or continue an investigation by
(a) making a false statement that accuses some other person of having committed an offence;
(b) doing anything intended to cause some other person to be suspected of having committed an offence that the other person has not committed, or to divert suspicion from himself;
(c) reporting that an offence has been committed when it has not been committed; or
(d) reporting or in any other way making it known or causing it to be made known that he or some other person has died when he or that other person has not died.
So there has to be an intent to mislead, there has to be concrete action (knowingly false statement or report, or fabricated evidence), and it must cause an investigation to begin or continue that otherwise would not have. And the same burden of 'beyond a reasonable doubt' applies. In practice I have rarely seen this charge laid and more rarely still succeed because proving a falsehood is very difficult. At the same time, the threshold for laying charges is quite high too (reasonable and probable grounds to believe), and in the vast majority of cases that I have seen where a charge has not resulted in a conviction, I can say in all honestly that I have almost invariably seen it as a gap of 'know' versus 'can prove', rather than a person actually being innocent in fact of the accusation. I'm not making comment on this or any other case in particular, but I woul dbet just about anyone working in the criminal justice field would probably agree it's an accurate generalization. Actually false charges are quite rare; what is more common is police/the crown ultimately failing to gather enough evidence and/or articulate it sufficiently to convince the trier of fact. So it would be very rare that something that is utterly, factually false enough to justify a public mischief charge would lead to charges being laid in the first place.
It does happen. But rarely.