Costco pizza

My son has a peanut / tree nut allergy & has been invited to a birthday party where they will be serving Costco's ready-made pizza. I called the local Costco & the manager at the food service counter was really thorough checking all the labels she could find & reading everything to me over the phone. She also said that they no longer carry the chocolate ice cream bars that they used to sell that had nuts on them. She was pretty certain that there is no shared equipment. However, once she transferred me to the administrative office to ask them as well, I was told that that cannot guarantee there is no cross contamination. Basically, they don't want the liability. I'm just curious what others' experiences with Costco are… Any feedback would be appreciated. Thanks!