This is the only time they were caught: https://en.wikipedia.org/wiki/2004_Israel%E2%80%93New_Zealand_passport_scandal https://en.wikipedia.org/wiki/2004_Israe

This is the only time they were caught: https://en.wikipedia.org/wiki/2004_Israel%E2%80%93New_Zealand_passport_scandal https://en.wikipedia.org/wiki/2004_Israel%E2%80%93New_Zealan... But it's safe to say that if they were caught once, they've probably done it numerous times.