Not in it, but when race marshalling there were two events which merged last year - one a race, one a sportive. The race was on a lumpy 25-minute-per-lap road layout which meant limited radio comms for the marshals, with race participants and the race convoy coming up a hill towards me and then turning left. The sportive came onto the road part for about two miles, then came up the same hill and carried straight on.
The race was doing their circuits however after about 30 minutes we had two groups on the road with a gap in-between - two in the break ahead in their own 'bubble' with the lead car and motos, then the main race convoy a few minutes behind. The first two sportive riders came into that gap, caught the lead two riders and passed them just before my marshal point. We figured out what was happening and got traffic stopped early to let the sportive riders across, who briefly stopped to watch, then got the convoy through.
I did suggest they should have been doing the race instead, but apparently the sportive offered free beer at the end to finishers.
For the next hour we had sportive riders getting (mostly) passed by racers so stopped traffic as needed but also helped them out. It was an "interesting" marshalling task working out whether they were on the sportive or part of the race as they came up the hill towards us, particularly for those dropped and no longer in the race bubble of the convoy.
Quite a few sportive riders liked having racers around them, particularly with very helpful race motos.