Not really - it's only easier to catch people that try to hide things that the IRS already knows. Nobody that was actually trying to cheat would ever do this i

Not really - it's only easier to catch people that try to hide things that the IRS already knows. Nobody that was actually trying to cheat would ever do this if the IRS was up-front about what it knew going in. What might happen more is that people don't correct the IRS's assumptions when they miss something and it's in their favor (accidentally or not). Whether or not this would significantly affect the bottom line, I have no idea, but I'd consider it vastly preferable to have them put more resources towards research before people are accused of cheating than to spend on enforcement after the fact.