The first thing to bear in mind is that the system this site runs on already tries to credit everyone it knows about. You can see this at the bottom of the pages where it says things like "This page was last modified 19:41, 9 Sep 2004 by Jon Simpson. Based on work by Steve Simpson and Maiden World Live user(s) BoBo.". The system can do that, because it knows who has added information to/edited the pages.
Obviously the confusion arises when some pages actualy have a Contributions section anyway. This is necessary when the site does not know about the person who provided the information, i.e. they havent added to/edited the page in the wiki (the most likely state of events is that the information has been copied from a text file or forum post by the original user). Because the system doesnt know about this person, it doesnt credit them, so to be fair we add an explicit mention for that person on the page.
Ideally, that person will eventually come to the site, and delete their name from the contributions section (if necessary, removing the entire heading of Contributions, if its empty). The act of editing the page to remove their credit will add their name to the real list of contributors, because the system now knows about them.
Actually, now I look back at this page, I'm not sure it will help clear up the confusion, but at least I tried..