Stealing from the government is not a kula. NO responsible rov says it is mutar unless you consider the Admou”r meCreedmoor responsible. It is ossur and a chilul Hashem.
It is a minhag that goes back to the times when we were persecuted and singled out for special taxes or sudden business closure by the Czars, Communists, Nazis and Muslims.
Fraud against government agencies has no place in the US, Canada, the UK etc although if Obama ruins the country during any second term (Hashem yishmor!) it may well be that the only way to survive will be by working under the table as is the case in many socialist or overly bureaucratized states including EY.