Given that any registered user can edit any article, it is, of course, possible for biased, out-of-date, or incorrect information to be posted. However, because there are so many other people accessing the content and monitoring contributions using the recent changes page, incorrect information is usually corrected quickly. Thus, the overall accuracy of information on the GCwiki is improving all the time. You are encouraged to help by correcting information, validating content, and providing useful references.
It is the responsibility of each individual who creates a page to maintain its accuracy. There is no way of enforcing accuracy. Each individual must be trusted to be effective in sharing information. It should be noted however that any user can and should correct that which they know is wrong.
As a reader you need to use your judgment about the credibility, timeliness, reliability, and accuracy of what you read on the GCwiki. Looking at when the page was created (via the history tab), and examining how many people have edited the page will help you judge what you read. Individual users' edit histories can also be scrutinized to see the kind and quality of information they are providing to the GCwiki community.
As a GCwiki user, feel free to contribute to the accuracy of its content -- that's the beauty of collaboration via a wiki!