I really hope this works for everyone. My neighbours are flying to Townsville via Melbourne in a few weeks. I gifted them lounge passes for MEL QP. They are in their mid 70s and not silly, but not tech aware as I found out.. When I went to their house to link the passes, they had no idea about checking in on line. Had never done it, didn't know how to do it. They said they would check in at the airport. So starteth the lesson!
They know they can get me around to do the CIOL, and I have told them to print their boarding passes.
Edit: I feel sorry for the customer service agents at airports. There won't be enough staff but plenty of customers.