People do what you do, not what you say. When pre-boarding is announced for people requiring special assistance, others will pick up quickly if a gate agent lets someone through that doesn’t fit the group. And for any group. If the gate agent lets that person through, it doesn’t matter what the gate agent says later. It”s a whole lot easier to take care of the situation before it snowballs, or preferably before it even starts. I find that Alaska gate agents often aren’t adequately upfront. They let it slide in the name of being nice and have a mess on their hands at a time when it takes a lot more effort to clean it up.