I was in the WI Costco last night where most cuts of beef are marked as being mechanically tenderized - even cuts such as wagyu retailing at $60/kg. We wondered if the labeling might be mistaken so asked one of their employees. He confirmed that they indeed tenderize pretty much everything apart from the filet mignon. He also claimed that most grocery stores sell tenderized meat despite not being labeled as such.
Once home, I looked into it but couldn't find a straight answer on the subject. One forum said that costco labeling was voluntary and not required by law. Is this a fact? I just don't understand how such a thing can be so prevalent.