I should accept my very own recommendation on hitting strings here yet don't. Stay quiet.
Amen.. FP26. I'm a coach as well and I learned a long time ago, every coach does things differently. Every player is different. What we might see as bad mechanics may be something that player developed to compensate for a weakness. Look at Craig Counsel, former MLB player. Would you ever teach a player to have the swing and stance he did? Probably not. Who would teach their players to wave the bat back and forth like Gary Sheffield used to do? But that was his timing mechanism. So I'm with you. If someone asks I gladly answer. The only time I might offer is if I see one where they are just getting their swings in and Mom or Dad is watching with only half an idea. Even then, I will ask permission to offer a tip. Usually, when approached in that manner, they are happy to have some help. But should they decline I would wish them a good day.