Unlike most of the responders, I did consider Barry to be a bit more responsible for the situation. It was clear that he hadn't forced the twins into anything, but he was the driver, so I consider him more responsible by default. On the other hand, as I pointed out to them, if any one of them had picked up the phone before curfew, they wouldn't be in trouble. At their age, there is no way, under normal circumstances, that I wouldn't have said, 'okay, but come straight home after you eat.'
With that understood, I tossed out a figure of three days without keys for Barry, and was trying to decide if four or five days without electronics would be comparable for the twins (and Barry, if he wanted to go with that option), but all three of them already knew that swats were going to be on the table, and they'd all opted for that.
Because I did feel that Barry was more responsible (should have been?), I gave him the option of three bare with the medium Lexan or four on boxers. It's not that there's a modesty issue involved with the three of them and me, and it's not like boxers provide much protection (IMO, at least), but it is both a psychological thing, and also it seems that the more choice they have, the better they take it. I offered the twins the same choice, with one less swat.
They all went for boxers.
I had all three of them strip to their boxers, then bend over the end of Johnny's bed.
These three haven't been in much trouble lately, and they don't have much experience with that paddle. I never try to hit out of the park, since I feel more, lighter swats is more effective. I might have been going just a bit easy Friday night, though - easier than normal, if not truly easy. I saw this as more of a wake up call, to let then know they're moving into a different realm and have to take little things into consideration now, than a real punishment situation.
Barry got the first swat, then I moved down to Josh and worked the line, until the twins had had their three, and Barry received four. All three of them were yelping and damp eyed before I finished, and Barry was a bit snivelly (well, all three of them were slightly snivelly, but Barry maybe a bit more).
Hugs all around, and I told them to go on to bed. When I checked on them later, all three of them were in Johnny's bed, and they looked amazingly similar to how they did 10 or 11 years ago.