I would love an option to disallow players to modify machine-config.
For pack authors, as an option for additional challenge, or for whoever would like it for whatever reason.
Another option to choose the default config form each machine would also be great to go with this.

This would also lend itself for additional nostalgia factor, in which times there wasn't much mods with machine configs.

I have implemented a way where via NBT Data a specific machine can be locked.
But a "default" to disable it for everything is something i personally don't want in the mod.
I can see why pack makers that build maps want locks inside the machine so it can't be changed, but to make all machines not configurable. I don't think its a bad idea.

on top of that this has nothing to do with "nostalgia". Its only really a inconvenience of all are disabled and nothing else.

" changed but all machines not configurable. I don't think its a bad idea. "
Can you rephrase that? I don't understand what you want to convey.