According to Facebook's documentation, page owners are no longer able to force users to like their page to gain access to content. This includes all competitions where you must like the page to enter it.
The liked field will no longer be returned in the page property of the signed_request object for Page Tab apps created from today onwards. For apps created before today, from November 5, 2014 (90 days from today), the liked property will always return true regardless of whether or not the person has liked the page.
After November the 5th, all of these competitions will essentially break as they'll think you already like the page.
What do you think? Good move by Facebook to stop forcing users to like a page, or bad move as it somewhat limits publicity for the competition holders?
Maybe people will only 'like' pages that they actually like now?