In fairness, I've received a few crazy notices from the IRS that didn't include the basis for an investment and just treated the MSRP of an asset as unalloyed income. Consequently, my wife nearly had a heart attack when she got a notice for $32k in taxes owed on a car we sold for $8k.
But also in fairness, this was because I misfiled. I amended the schedule C and updated the bluebook value of the vehicle, the purchase price, the sales price, and the net income. Ended up owing a few hundred bucks.
But if I hadn't had a decade of experience filing the arcane nuances of American tax filing, I could understand going into a panic.
My favorite IRS notices are the scary you owe us letters that always say somewhere in normal font "if you have already paid or started a payment plan you can disregard this notice." Sometimes you can get those letters months after paying. To be fair, my taxes are complicated, but boy do they really need Congress to give them money to modernize their systems.