If you make a mistake on your tax return, the government isn't going to put you in jail, but if you make a big mistake on your tax return and it was accompanied by the willful knowledge that you intended to make that mistake, the situation is different. For instance, if you said I'm just not going to report any income or I'm going to try and conceal income so I don't have to pay taxes ie. I'm going to evade taxes or if you deliberately file a tax return that's false or engage in any of the tax penalties, yes you can go to jail for that. The auditor is not going to be the one that puts you in jail but what happens is with civil audits, which are a great referral source for the criminal division of the IRS, a lot of times what will happen is the government will engage them and they call it a parallel investigation. They'll have a civil auditor who's conducting a civil audit, the auditor will find something, and they will report it to the criminal division.
Then what will happen is usually before they report to the criminal division, the civil auditor will use the civil audit as a fact-finding mission to gather more information to give over to the criminal authorities. So I would hope that if you get audited and you know that there's a serious error on your return that you're engaging with an attorney immediately to step in. That's probably the most important part, but yes you can go to jail for deliberate mistakes on your taxes. You can go to jail for trying to evade taxes or filing a false tax return. Probably one of the most important things is you should not make false statements to an auditor, so again one of the reasons you get an attorney involved is to minimize your own contact with the civil auditor because if the civil auditor asks you a question and you lie about it, they can use that against you later. You know the old saying you have the right to remain silent and anything you say can and will be used against you in a court of law? You should treat the civil auditors that way. You're talking to a government agent that government agent is conducting an investigation into you, so don't say anything that will be damaging to you later. If you're in a situation where lawfulness is even an issue, you definitely need to consult with an attorney as soon as possible to help you deal with the situation.