If birth comes on really quickly at home, and you have to accidentally birth, with ambulance called at the last minute, what would they do? Prosecute you?
It's legal for you to have a birth at home (or anywhere else!), it's just that if you have a private midwife with you, SHE is breaking the law (you're not though). So while you wouldn't get prosecuted, your middy, if you had one, would get a $30 000 fine.