Sacred Haven of Debauchery

How can a regular user attempt to edit someone else's message? After reading this, I suddenly became curious. It seems like this question has already been raised, hasn't it?

The idea is to insert this into the address bar:

http://forum.heroesworld.ru/editpost.php ... itpost&p=n

where n is the message number. However, the forum, or rather those who wrote its engine, turned out to be so insightful that they don't allow random people to perform such manipulations.