All examples of people who claimed to owe less than they did. You need to provide an example of "I owe $10000; I don't have it" going to prison. Re: [1], at some point they start freezing assets and collecting the owed amount on their own, but you remain free to walk the streets.
I'm looking for that exemplar (someone who filed a tax return saying they owed more than they paid, and didn't pay anyway). The common cases seem to be, as you point out as well, either a tax return that justifies not paying the tax via some sort of reasoning, or simply not filing.
