Cops Checking ID's At Bars

From the Wisconsin Rapids Tribune: Appleton police are using cutting-edge scanner technology to keep convicted criminals out of some of the city’s most popular bars, but civil libertarians are crying foul over a practice that could spread to other communities.
While authorities claim the innovative strategy of checking bar patrons with an ID scanner is making the community safer, the process is raising red flags among some people, who say it amounts to an invasion of privacy.
The technology doesn’t give any particular thought to privacy concerns since everybody who enters gets scanned,” said Chris Ahmuty, executive director of the American Civil Liberties Union of Wisconsin. “It could be a hardened felon on parole, an attorney from a law firm on College Avenue or a 21-year-old Lawrence (University) student. There’s no distinguishing between who gets targeted, and that’s a problem.”
The crime-fighting tool, which has the blessing of several Appleton bar owners, is designed to act as a clever dragnet to identify bar patrons who violate their probation by entering the clubs, or those who are being sought on criminal warrants. Police agencies from Milwaukee to Wausau are interested in following Appleton’s lead.
Critics say the scanners also allow business owners and police to snoop on the bar-hopping tendencies of thousands of law-abiding residents, and walk a fine line along the Fourth Amendment regulations against unlawful search.
Appleton police officer Adam Nagel said there is nothing nefarious about the scanner enforcement program.
“This originated as a way to check fake IDs, but we saw potential for what else we could do with it,” Nagel said. “We found the probation and warrant aspect was strong. You’re not only deterring underagers, but preventing convicted criminals from causing problems downtown.”  http://www.wisconsinrapidstribune.com/article/20130601/WRT0198/306010148/Has-Big-Brother-arrived-Police-use-ID-scanner-bars-nab-criminals-civil-liberties-raise-concerns?nclick_check=1
I understand the cops view to a certain extent, but chances are the college pubs the likely place for convicted felons and people with warrants hang out?
So, isn't this like the cops walking down the street and asking for your ID without cause?
I would love to get those who have warrants and violating off the streets but the cops need to do it legally and I don't think this legal.
OMG, I agree with the ACLU..... hell has frozen over.