Huh, never experienced that personally, or heard an example from anyone I know. I guess if it affects too many upright citizens it'll go the way of stop and frisk.
I know CA is so fastidious about accurately calculating personal income tax that they once issued me a refund check for $.50. Not sure how trustworthy the fed is by comparison, but my taxes are simple enough I can calculate what I owe in about 5 minutes and as long as I pay it when I'm supposed to they don't seem interested in fxcking with me. Even got a few extensions when I was younger. Don't have any data points regarding the prevelance of mistakes on their end, nor the outcomes of disputing those mistakes. I've heard that electronic filings are generally not subject to audit, probably because the IRS is more concerned with people who DON'T file their taxes, but that could be a myth.
TL;DR, murder the tax prep industry, streamline federal income tax and put tax dodgers in prison. I'd be happy to see my tax dollars funding that.