So they send you a bill and you send back a form that says "here is a thing you didn't know about that changes the math".
87% of tax filers could have their taxes filled out by the IRS because they IRS already has all the information.
87% of tax filers could have their taxes filled out by the IRS because they IRS already has all the information.
And marriage and death records are public, as are probate. So they would have all of that too.
Or simply ask you if the most common situations apply to you, just like turbotax does.
The IRS could send a tax bill for what they do know, with an option to agree that is all you owe and pay, or an option that you will need to file the taxes yourself because they are missing information.
For the vast majority of Americans, option 1 will cover them.