I think a number of circumstances must be true before a failure to declare income might be consider "okay".
1. You and others in your position must have little or no say in the political process and no legal means to bring about meaningful change in politics.
2. The taxes you pay must be high enough that they substantially impact your quality of life.
3. The government is not using your tax dollars to provide the services you need.
If all three of those are true, then I'd see nothing wrong with those individuals fighting to keep the money they earn regardless of what the law says they should pay.
Completely arbitrary:
1: This is completely irrelevant, if you look upon what kind of society Jesus and those who heard him say "render unto Caesar..." lived in.
There WAS no say for the common man in running government, and certainly not the common JUDEAN man. Didn't matter to Jesus.
2: Who gets to determine when this criteria is met? Maybe I feel my "quality of life" depends on having MUCH more money than you do. Are you then saying that I would be right to cheat on my taxes, but you wouldn't?
3: Related to #2. What if I feel I need a free car, and government isn't providing it for me? Moreover, I don't have kids, so why should I have to pay for schools, etc?
There is ONE criteria and only one:
Has the authority of the country in which you live, decided that you should pay this percentage? If yes, then you pay, plain and simple. We are called to obey Caesar's laws no matter how unfair they might seem to us, SO LONG AS doing so does not force us to break God's laws.
Jesus talked about rendering under Ceasar what was his - I think you'd have a tough time making an argument that the Roman Empire was more worthy of their tax dollars than the American government is of yours.
Who gets to determine whether or not a particular country is "worthy" of taxes?
Wrong by whose standards?
The IRS & Federal government would tell you that you're wrong based on the US revised code...
However, from my personal opinion, I wouldn't say you were wrong for doing so.
So....we can pick and choose which laws we want to follow, based on how we personally feel about them?
So, those involved in the American Revolution were in sin?
Was it a sin to rise up in rebellion over minimal issues, which nowhere NEAR a majority of the colonists supported?
I'd lean towards yes. However, it is a testimony to the greatneess of God, that He turned something that was originally sinful, into a blessing the like of which the world hasn't seen for centuries: The USA.
Is the call to pay Cesar a call for stasis?
I think I made myself pretty clear: Unless Caesar's laws necessitates breaking God's, then Caesar MUST be obeyed. The First Church understood this. The Early Church understood this, even when Caesar was persecuting it quite ferociously.