There are often templates that link to whois-pages to make access to IP-related information easy. However, there are many, many providers for a whois-service and each one is different (with ads, without ads, different layouts, etc.). If you have a wiki, where anonymous users can make edits which are saved under their IP address, then whois is a basic tool in the wiki, and should imho be provided (perhaps through an extension?).
Pros are: The user doesn't have to leave the site; fair and equal way to resolve this matter; no ugly external links that may require the user to enter Captchas.