In New Zealand I am obligated to tell any policeman who asks my name and address. I am not obliged to show ID unless I'm driving, in which case I must show a valid drivers license.
My son recently was asked for ID by a policeman outside a nighclub. He politely told the policeman his name and address and refused to hand over his ID.
The policeman took it in reasonable spirit, but did say "how do I know if you're telling the truth?", to which my son replied "That's really not my problem, is it?".