I am one of those "dreaded" public relations professionals that many are worried will spoil Wikipedia :-) I have worked in the field since 1994, when I graduated from George Mason University. I have never edited or made comments to a Wikipedia entry unless I had much more than a passing knowledge, you can even call it an expertise. I also always disclose my identity and position. If you would like to learn more about me and my opinions, I have a blog called Communication Overtones where I give my thoughts and opinions about the field of PR.
Wikipedia and PR Professionals edit
I am fully acquainted with the principles of Wikipedia, including the NPOV, Verifiability and No Original Research. I also think that PR pros are more than capable of fulfilling these requirements, and indeed feel that the regular user is more likely to violate these rules that most PR experts.
A saying about throwing the baby out with the bathwater comes to mind with Jimmy Wales most recent rants against the PR profession and Wikipedia.
If you banned everyone with a certain POV from editing Wikipedia articles, there would be no one to edit, since everyone with interest and expertise enough in a subject has a some POV. The questions are, can we subvert it to make a change and will the community keep tabs if we don't? I think the answer to both questions is yes.
Not all Wikipedians feel the way that Jimmy Wales does, I especially like Joe Mabel's advice to PR professionals and think everyone should read it before attempting one edit in Wikipedia.