This happens on sites that are generally poorly coded and they wish to protect themselves from hackers. What hackers can do is capture the HTML code, say to an eticket page where you are asked to pay $1200 for a ticket and then they replay the page back with a modified amount - of say $400. The application doesn't check that the amount being returned in the web form is different from what it just sent to the user and then it stupidly goes ahead and does the transaction. This trick has been closed for a while in many sites but many poorly coded sites still suffer this style of attack. One way to mitigate this type of attack if you are not sure if all your HTML apps are properly coded is to not allow bookmarking deep into your app and then allowing jumping to there. It would appear Elal is taking that preventative measure.

-Hank