Since neither notified the scorer, they both are gone.

As others have said, I would have had to witness the change or have definite knowledge of it. Because the penalty is so severe, I want to be damn sure before I make this call.

I can't think of any legitimate reason for two players to switch jerseys after the game has started.

A legitiment reason:

A1 jersey gets saturated with blood. He must take a jersey from a bench warmer in order to continue playing. So in that situation numbers and the scorebook would have to be changed.

Yes, including the fact that there is no Technical foul for this "legal" switch.

Also including the fact that the kids should tell the table, or at least their coach.

The part about this subject that troubles me is how it could happen without the refs or table realizing it in the second half. Or coach. If it really happened, wouldn't someone think, "Wait a minute, that kid with the green hair was 21, I'm sure! How could he be 53 now?" The only reason I can think of to switch jerseys woulc be because of foul trouble, and then wouldn't he have come to the ref's attention, face plus number? I don't know, I just wonder if it really happened. Also, I can't believe the coach wouldn't know. So did he lie? Well, sure it's possible, but...

There's one other option.If they can find a shirt for A1, as per casebook play 3.3.6SitA(b), they don't have to use a sub's shirt.