If I remember correctly (I don't have that book with me) The Mouth of Sauron called them spies, did he not? Therefore I truly think that Saruon believed them to be spies possibly on some covert operation to disrupt some internal affairs. It was told to the captains of the west in hopes of reading some of their thoughts and intent, hoping that some information could be gleaned for their benefit.
If Sauron had any inkling that Frodo, the spy, possessed the ring he would not have opened the gates and used his forces to search for Frodo and the their quest would have been in vain. Rather Aragorn, Pippin and Gandalf through 'chance' and strategem were able to convince Sauron that the hobbit who had originally possessed the ring was with the captains of the west. If you remember it was stated that the plan was that Sauron, believing the ring to be with them, would take the bait and ensare the person who claimed the ring for himself. That was the beauty of this plan. Sauron truly thought that Aragorn or Gandalf had claimed the ring and came prematurely to show their new found strength.
__________________
“I wish it need not have happened in my time," said Frodo.
"So do I," said Gandalf, "and so do all who live to see such times. But that is not for them to decide. All we have to decide is what to do with the time that is given us.”
|