173Visa ceases if holder enters in way not permitted

173  Visa ceases if holder enters in way not permitted  (1) If the holder of a visa enters Australia in a way that contravenes section 43, or regulations to which that section is subject, the visa ceases to be in effect.  (1A) A maritime crew visa held by a non‑citizen does not cease to be in effect under subsection (1) if:  (a) the non‑citizen travels to and enters Australia by air; and  (b) at the time the non‑citizen travels to and enters Australia, the non‑citizen holds another class of visa that is in effect.  (2) To avoid doubt, a non‑citizen child who is taken to have been granted a visa or visas, at the time of the child’s birth, by virtue of the operation of section 78, is not to be taken, by virtue of that birth, to have entered Australia in a way that contravenes section 43 or regulations to which that section is subject.