Too many people breach Facebooks rules ALL THE TIME…. Especially with competitions.
Running a Facebook Promotion Requires an App:
Much has been written about the Facebook Promotional Guidelines and how to run a compliant promotion. The guidelines have evolved, but the most important requirement remains the same: any promotion (i.e., something where a consumer enters for a chance to win a prize) on Facebook must be handled through an app.
If you know what you’re doing, you could develop your own Facebook app, but you might prefer to personalize an “off-the-shelf” app by a variety of companies such as North Social, Wildfire or Strutta.
Some are inexpensive and no-frills, while others provide a more robust set of features and options to connect you with your customers and personalize the experience.
If you choose a third-party app provider, choose a Facebook Preferred Marketing Developer so you can feel confident you’re in compliance with Facebook’s platform policies.
via 8 Tips for Running Social Media Promotions | Social Media Examiner.

