Not to say etiquette isn't arbitrary, but the two top results (all I bothered to check) for my search about silverware placement suggests that the "correct" order is fork on the left, knife first on the right, then spoon furthest right. This is, indeed, alphabetical order.
So while it may be arbitrary, it isn't arbitrary on an individual level.
Ewwww arbitrary!
Not to say etiquette isn't arbitrary, but the two top results (all I bothered to check) for my search about silverware placement suggests that the "correct" order is fork on the left, knife first on the right, then spoon furthest right. This is, indeed, alphabetical order.
So while it may be arbitrary, it isn't arbitrary on an individual level.