I responded to this a bit in my previous post. I think if someone is making the case that the three clue rule squelches a virtue of play, it is more on the person taking that position to make their case than on people to defend the three clue rule. At least it needs to be made clear why they think the three clue rule squelches important choice making. I think something like the three clue rule is pretty neutral on this front. It isn't aiming to actively promote it, but doesn't detract from it. And it can be used to promote meaningful choice. Its reason for existing isn't to solve the problem of a lack of meaningful choice, but to solve the problem of investigative bottle necks (and it is a direct response to the Gumshoe 'systems' approach by offering an 'adventure structure' approach).
So if someone has a choice to make, what will make that choice authentic? I would think that they're not deceived about the nature of the choice, and they reasonably understand the nature of the choice and its implications.
Would you agree with that?
That's how I've approached this part of the conversation.
So take that and then think of the three-clue rule. The rule states "for any conclusion you want the PCs to make, include three clues."
What does this do? It works to keep play (typically investigative type play) on track. It works to ensure that the players will find the information they need in order to proceed to the next scene. It's already determined what the next scene will be. The conclusion is already decided by the GM. It's right there in the rule.
Does that sound as authentic as the players taking actions and gaining information and then deciding what to do next or how? It doesn't to me.
I don't know if I'd consider the three-clue rule full on railroading because I can imagine examples that still play out differently than expected by the GM even when deployed, but it's certainly closer to railroading than not. Chances are certainly higher that play will go the way the GM has decided it will go. I mean... it's designed to do exactly that.
Again here I think authentic play doesn't work well as a term. But if we are talking meaningful choice, I definitely think D&D alignment rules can be used to enhance that (for reasons I stated in my other post). Obviously alignment is one of the more divisive concepts in D&D so some people don't like it, or won't agree. But taking away meaningful choices or reducing authenticity isn't a problem I have found with it (I have certainly encountered other issues with alignment, such as how individual alignments are defined). I found it to be a very powerful tool in Ravenloft, precisely because it makes moral choices meaningful on a level that impacts the characters physical form.
I don't think this is really what was meant by GM enforced alignment. I don't think alignment in and of itself is the issue, it's when the GM enforces behavior of players based on alignment. The idea that a character could shift alignment in some way... either at the player's wishes, or at the GM's suggestion based on what the character's done... doesn't seem inauthentic as it relates to the discussion.
Barring actions based on alignment was more how I took that. Again, I don't think alignment is an issue, but I can see how the GM taking too firm a stance on it could be an issue.