Daisy, in the States, the most venerable version we have is Cliff Notes. I always found it amusing that when classmates would complain that they couldn't find a book at the library, I would go and see that all the Cliff Notes versions would be checked out and impossible to find while there would be a zillion copies of the original novel lying around.
Returning to the current topic, I think someone brought this point up already, but the movie (FotR) does indicate that
Saruman is in it for himself and not necessarily serving
Sauron. When Saruman asks the
Lurtz orc whom he serves, Lurtz lets out a full-throated "Saruman!" The fact that Lurtz does not hesitate, does not appear the least bit confused ("Sauron? I mean...Saruman!") and says it with all the gutso that Saruman has given him makes it clear enough (at least to me) that Saruman's previous actions and statements were a bit of a ruse. True, one never actually hears Saruman say "Go jump in a lake of molten lava, Sauron! I'm taking
the Ring myself!" But I think most moviegoers don't need things spelled out for them (at least not all the time).
I agree that Saruman's statement to
Gandalf that they must join Sauron because he is too powerful comes across as a bit crass. Being the skilled and polished speaker he is, Saruman should have known better that Gandalf wouldn't fall for a line like that and certainly wouldn't respond to that kind of logic. I would have expected something much more suave (or at least oily) from him.
But I don't find PJ's decision to mislead folks that Saruman is serving Sauron to be wrong. Misdirection is an important part of entertainment from horror thrillers to magic tricks, and even
Tolkien engaged in a bit of that during his
books.
So what's the big deal?