I am happy to know that you are ethical in all your dealings and accept no deceptive practices from clients, employers or associates. Bravo. Don't worry, I don't usually do business with anonymous parties anyway. In US law that would be illegal, and thus unethical. can it be viewed as professionally unethical to post anonymously in a professional forum?

Back to the beholden point. The rule of local law is never deceptive in the eyes of the citizens of the jurisdiction, whether one agrees with the law or not. Thus you must, in order to not break the law and then become unethical, not break local law.

Generally, breaking any law, local or otherwise, is unethical: it violates the ethical value of citizenship if you are a citizen and the legality of your visa if you aren't one. When a law is judged by an individual as immoral, unethical, unjust or unfair, (countries, states and other types of legal jurisdictions pass bad or stupid laws quite frequently) if one is a citizen of that jursidiction it could be their civic duty to work to get that law changed but not to break it. For non-citizens, changing a law is in the realm of international diplomacy or for international legal adjudication (The Hague), not for business people unless it can be remediated in a legal contract. If you are a non-citizen, your ethics must be aligned with the local law of where you are doing business or you are a lawbreaker which is viewed by most as unethical.

When you work overseas (as most American multi-national companies have many times become painfully aware when they find out that fixed ethics can be a devastating business problem) you have to work the narrow path within two sets of laws and two sets of ethics which sometimes conflict. You have the laws of your own country (and we can spend a lot of time on what your "own" country means) and those of the country of business transaction.

BTW, next time you enter a foreign country on a tourist visa to make a one day business pitch or to look at some code or even take a customer out for entertainment you are tecnically breaking the law and thus unethical. You should have gotten the expensive business visa and possibly a business license. That's the most common breach of law and thus ethics.