SHAFAQNA – The Grand Ayatollah Sistani answered a question about deceiving people in non-Islamic countries.
Question: Can a Muslim in a European or American country steal disbelievers’ properties? And can a Muslim seek to earn money by ways which are usual among them? And use those their methods?
The Grand Ayatollah Sistani: Generally, stealing public or private property is not allowed; and it is not allowed to waste it either, even if that action does not harm the honour and dignity of Islam and Muslims; but because as (a Muslim) has undertaken to abide (by the laws of the country) at the time of obtaining visa, it is considered as deceiving and is against the agreement, because betraying and deceiving any one and in any way is Haram.
Source: PERSIAN SHAFAQNA