What would have happened if Frodo had left when Gandalf told him?

I would also like to add this "what if". Although all this conjecture is rather moot, I will put forth another possibility. The Company of Five (Gandalf, Glorfindel, Frodo, Merry, Pippin and Sam, as I said in my previous post), may well have been found by Theodred and his company in the Gap of Rohan. Gandalf may have, after going to Edoras and speaking to the king, gone to consult Saruman, and thus learn of his treachery. Had he escaped in the same manner (being rescued by Gwaihir Windlord), he could have gone to consult King Theoden, and thus saved the life of his son Theodred and halting Saruman before he amassed his army, the Uruk-hai. Quite a different and yet similar story. Absurd and pointless, yes, but entertaining.