Same here - robo call about tax evasion - ignoring this information would be considered an intentional attempt to avoid an initial appearance before a magistrate judge and would be a criminal offense.
Obviously these idiots have never heard of due process in this country. If the IRS were truly after you, they would first contact you by mail. Then you would have a chance to hire an attorney and/or accountant to correspond with the agency. Then maybe an audit and, depending upon the results of the audit, possibly an appearance before a magistrate or some other judicial authority. There is no way the IRS can call someone out of the blue and threaten tax evasion. And even if they did, it wouldn't be a robot calling.
I have to hand it to these shysters, though - at least they are using a 202 area code from Washington DC, so it seems somewhat legit when you first notice the number. I have received calls in the past from New Hampshire area codes with the person on the phone speaking with a heavy Indian accent. Seriously - how many Indian IRS agents live in New Hampshire? When I asked the idiot how much he wanted he quoted something like $5,000. Sure - the check's in the mail.