It’s an interesting one, and a valid point on the average rider over the entire event. However, I do think there is a fairly big difference between the average rider in the first few waves and the average rider in the second half of the waves.
I think the average rider in the second half of the waves will be fairly comfortable ticking over and not too worried about pace etc. The average rider in the first few waves will be a pretty different proposition though as they’ve put down a quick time and will want to push for that. I know of a few clubs with riders in waves B & C that will be catching up fairly quickly and this is likely to create the bunching behind the car.
Even though it’s not a race, it feels safer to let everyone go at the pace they want to go at and then it will at least separate out a bit into groups that are travelling the same pace and are comfortable with each other.