Fakeing the PR of a site is easy enough but pointless unless you're trying to sell it to a dim-wit or are trying to sell high priced links based on the pr to a clueless webmaster. It doesn't get you any traffic.
All you have to do to see if the pr is faked is a search in google
info:fakesite.com
if the info is there and refers to the site then it's not faked, if there's no info on a high pr site its suspicious, or more usually the info is for the site it's been redirected to.