mnmracer – as you say, I suspect that keeping the lapped drivers in the train rather than have them scooting round is important, I think also the time it takes to have them catching the end of the snake means that even more time is spend behind the safety car.
I think (for what it’s worth) that the lapped drivers should hold station, partially for the “train issues”, but it’s also hardly fair that a driver in the lead (a) has his (or indeed her!) time advantage wiped out and (b)has their advantage of having already passed through the traffic wiped out too. Although I do miss the effective rolling starts that you used to get.