A good short term strategy when attempting to prevent something is to use obviously false arguments. This is a good strategy because even false arguments can be believed if they are stated with a sense of conviction. But this is a crappy strategy in the long run since it undermines the credibility of the fool making the false argument.
One of the arguments against open access is that open access will ruin the peer review system. This is obviously total bull but stated with conviction by publishers it sounds almost credible. It sounds very credible to those who have no idea what peer-review is. It sounds even more dangerous when the importance of peer-review to the progress of science is explained.
So people tend to get nervous when open access is invoked and fear for the demise of good science. Therefore it is always a good thing to have a answer to this prepared.
Peter Suber’s article in the September 2007 SPARC Open Access Newsletter is just what you need – please read Why Open Access Undermine Peer Review?