In Reply to: Smudge UK is partly right posted by JennyWren on Wednesday, 16. February 2005 at 17:25 Bali Time:
Expats on a KITAS visa (is it still called that? I get lost in acronyms in Indonesia) have to register, but as far as I know it has never affected anyone on a tourist visa.
Also, I believe (not 100% sure) International Law states that it is illegal to deprive someone of their passport (except by certain authorities if the person has committed a crime), even if the passport has been left as security against an unpaid debt.
Giving someone access to your passport for a week or so is a much bigger security risk than not showing it at all. I wouldn't do it on principle.