For real. This is how the system ought to work. If they have the resources to come after you if you accidentally filled something out wrong, they have the resources to fill it out right for you in the first place. The tax system in the USA is nothing short of a farce.
To be fair, the IRS does not "come after you" if you make a mistake. They send you a letter, with request for the additional amount due, and if you agree, you pay it. Done.
Happens all the time. I got one from a State once, and I'm still convinced I was right and they were wrong, I'm not exactly going to argue with them, when they're sending me money.
However if you report more interest, or wages than they know about they will take your numbers as is - they assume you are reporting under the table income. They will however fix arithmetic errors, and give you credit for things you should have asked for (dependent deductions for example).
