Is it Illegal or Legal to Scan ones ID?

I am a cashier in a West Virginia beer and Tobbaccoo outlet where we have upgraded our systems to An I'D scanner. In which means a customer must provide a valid not expired I'D or drivers license. In which must be scanned where on the screen as in have been willing to share the process wi th customers only provides me and the computer with.a date of birth and age. Stating that accepted or rejected meaning I can or cannot sell them beer or tobbaccoo products. However many has claimed it as illegal, a violation of the constitution to require an I'D. I'm doubting it is illegal, ( we all know WV loves conspiracy theories) However many has threatened to sue over the fact they cannot buy beer without thier id being confirmed by the computer.

It is also rumored that anywhere in WV will have to have these scanners if they sell alcohol or tobbaccoo?

I am curious with the fact that I fought with the customer on this telling him i refuse to sell him without it until he threw his IF at me telling me he was taking me and the store to court over this.

I responded with " cool. Ill wear a skirt" because I doubt it's illegal. However I am asking because I'm hoping to get to the bottom of this and figure out for sure if it is or isn't legal.