Given a reviewer pool whose diversity of expertise matches that in your pool of authors, bidding works fantastically. *But everybody needs to bid*. The only problems with reviewers we had were with people that had failed to bid.
It might be reviewers who don't bid are less committed to the conference, more overextended, more likely to drop things in general, etc. It might also be that reviewers who fail to bid get good matches become less interested, willing, or able to do their reviews well and on time.
Given a reviewer pool whose diversity of expertise matches that in your pool of authors, bidding works fantastically. *But everybody needs to bid*. The only problems with reviewers we had were with people that had failed to bid.
It might be reviewers who don't bid are less committed to the conference, more overextended, more likely to drop things in general, etc. It might also be that reviewers who fail to bid get good matches become less interested, willing, or able to do their reviews well and on time.