If the IRS would "ask" me about income in the same way that I "ask" my wife to pass me the peas when we're having dinner, you can be sure I wouldn't be paying any taxes...

That's not quite right. The case you cite does support your position. But, the bar for jail time is a higher hurdle for the gov't to surmount than that. You merely have a good faith belief you did not violate the law. Therefore, if you are handling a gray area and you know the IRS could take a different position, you can still rest easy about jail time so long as you don't intentionally deceive/lie/etc. This is not legal advice

Also, if you and they don't find a mistake for a few years, there is a statutory limitation on them even collecting money. I don't remember exactly, but it's less that I'd thought.