This actually did happen (or close to it). It wasn't a red-head (sorry, Stoney - I just happened to like that picture). It was Parker and Brad Tower.
I went close to what most of you did. I honestly don't think that calling when you're already 20 minutes late, then expecting to not get in trouble is a good idea. If they'd called a few minutes before 6pm, and told me they couldn't make it home on time for the exact same reason, I would have been more understanding.
On the other hand, I do want my boys to get into the habit of calling me and updating me. Instead of the spanking that I think they'd earned by being more than 30 minutes late without a good reason, they each did their age in the corner (Jim was already here, so Brad got to go home and do his there). They're also restricted from their bikes for the weekend. I would probably have restricted them to the house for one day normally, but they had the birthday party Friday night, and I wasn't going to take that away from them for something like this - so, bikes.
I did thank them for calling, I clarified that it's not a get out of jail free card, and that if the same thing happens again, they will get spanked. While Brad is pretty nervous about the idea of a group spanking like that (even just two boys), they agreed Jim and I were being fair, and no one was too unhappy (except maybe some of the Spankorama readers).