This Utah law requires perfection.
So in theory sites could block all VPN users (if you can somehow "perfectly (1) detect VPN/proxy users"), but if the law necessitates that nationally/globally then it's unconstitutional anyway. It's the age assuring of VPN-users specifically from Utah part that Utah are relying on being possible for the law the be constitutional.
A VPN/proxy could exist on any given IP address at any time, which the California law recognizes but the Utah law does not.
Heck, Lowes and BestBuy are pretty unusable in general via VPN already.. (or maybe due to ublock, or privacy badger or eff, etc.. :-)
Unfortunately know this because a gambler friend showed me.