Even people who fly formation for a living make mistakes:
https://www.youtube.com/watch?v=Rluka-hdphI
Dissimilar aircraft formation is even tougher. I lost a friend that way and he was a damn good lead.
Flying in close proximity to someone who lacks the maneuverability to get out of your way puts all the onus on you. Not sure it ought to be done at all unless you do it regularly, and certainly not over a crowd.