There's also all kinds of not necessarily intended communicaton from the guessers in the fact that you can listen to which words they were considering and didn't pick. Nothing in the game attempt to say that you should not consider, say, whether they were going in the right or wrong direction in their guessing, but it sure can make a difference in how to approach later clues. If they were being very wrong, there might be a need to double up on words that you intended, and that your guessers missed.
In the same fashion, nothing in the game saying that I cannot listen to those guesses as a member of the other team, whether guesser or spymaster, and then change behaviors to make sure we don't hit words they considered as candidate words without very good reasons. Let them double dip on mistakes, or not make their difficult decisions easier. It's not as if the game demands that everyone that isn't currenly guessing should wear headphones to be sure they disregard what the other team says or does.