Forced spindown before race

I think calibration of the trainer is important and should be required to do before entering a race. Some are not aware of or don’t care about spindown.
If we where required to do a spindown before entering a race, some miscalibrated trainers could be avoided. This would potentially result in more fair racing

Of course the problem here is the trainer could be cold having joined the event say 60 seconds prior and not had time for the tyre to warm up if a wheel on trainer.

Off course. You would have to plan for it. What if the spindown was something you were taken to when you entered the race, and you could e.g. be required to enter at least 5 minutes before the race start. The spindown could start with a 3 min warmup and then the spindown. I know the Zwift app saves the last time you did a spindown, so if you had already done a spindown that day, you would not have to do it again.