In all but the most severe cases, if the courts won't force a drug saliva of hair follicle test on an abusive parent because it's too intrusive, then I doubt this would fly either. It's a dead horse, if not now, then when it's challenged.
C46 would give police the right to demand a saliva test from any driver they pull over with no cause needed. It's a bullshit law that won't pass as written.