Facebook already announced that it would no longer support business pages to have Like Gate’s type of applications where user need to like their fb pages to enter into the contest or receive points in the game. Which means there is no way to track if the user liked the page or not.
As per facebook:
The ‘liked’ property will no longer be returned in the ‘signed_request’ object for Page Tab apps created after today. From November 5, 2014 onwards, the ‘liked’ property will always return ‘true’ regardless of whether or not the person has liked the page.
Facebook changed platform policy:
You must not incentivize people to use social plugins or to like a Page. This includes offering rewards, or gating apps or app content based on whether or not a person has liked a Page. It remains acceptable to incentivize people to login to your app, checkin at a place or enter a promotion on your app’s Page. To ensure quality connections and help businesses reach the people who matter to them, we want people to like Pages because they want to connect and hear from the business, not because of artificial incentives. We believe this update will benefit people and advertisers alike.
The practice of incentivizing users in exchange for liking a page has been for years, which had helped them to increase the number of fans for their brand and overall to increase reach to their customers. However, now this is not possible.
Facebook wants your fans to really like your brand/page, not only your contest prizes or materials that they get from liking your page. Forceful likes, doesn’t really mean they want posts from your page on their walls or they really do care for your brands. Lets say you ran a contest to win an Ipad and user need to like your business page to enter into the contest. You might get an increased number of likes running this contest but you must be aware that people are liking your page not because they like your business or they really do care about your brand.. they are just concerned for Ipad as they are Apple fans..:)
Overall, this announcement by facebook seemed fair enough for users as they connect with a business or brand only if they truly want to and not because they were enticed by “artificial incentives”.