Confused About DABS Rules

So I had a weird experience today and was hoping someone could shed some light on this. For the record, I’ve lived in Utah for 7 years so I’m pretty aware of all the weird liquor laws.

I went to the liquor store today along with my son to get a gift for Father’s Day. During checkout, my son was handing me the items and the clerk refused the sale because he had touched the alcohol. I was confused, but asked if I can just call my husband to come and purchase it instead, and she said no because my son had already touched it. Eventually the clerk decided to sell it to me cause I was super confused.

After leaving I checked all the signs in the store and googled if there’s a specific law and couldn’t find anything that says a minor touching alcohol while shopping with a parent prohibits the sale. I did read that it was up to the clerks discretion, but my son is 4 and he’s not secretly soliciting people to buy him booze. Has anyone else run into this at a DABS store, or know if this is an actual policy?