I don’t need to present any proof, as I’m not making any assertions. I asked you a simple question.
In general, failure to file a state income tax form is either a civil infraction (pay some fine, file it, and you’re done) or extremely minor misdemeanor. A prosecutor going after Snowden in a desperate bid to make him spend 30 days in a county lockup is going to look like an idiot and hurt his career pretty badly. Tax evasion is usually a serious crime, but requires that you actively hide income or file a false return, not that you just don’t file a tax return. I know people who went for years without filing one and the biggest penalty is that they couldn’t claim their refund on any older than three years.