This is where I believe it was Tom Doak’s idea for architects to choose a few courses they designed that would never be purposely altered or “improved” 
The idea definitely has merit but not sure how it gets/stays implemented long term.
Well, it won't go far if I'm the only one who ever does it, but I do intend to try.
The only way it stays implemented long term is by pressure . . . presumably the course in question is still using the architect's name and that connection is valuable to them, so if, say Harry Colt hadn't just said Swinley Forest was his "least bad" course, but instead "the course I hope is never changed," that would apply a little more pressure to the decision to change something.
[Of course, the club's greenkeeper could just go out and rebuild some bunkers "for drainage" and totally eff them up, and then 20 years later you'd be fighting about preserving THAT, but I digress.]
Unfortunately, I think it's the opinion of most architects' societies that nothing is sacred, because most of them want to make money on renovations, even though they have now taken pains to copyright their own work.