Typically you can expect a very minimal (~10%) drop-off rate for your contest due to a like-gate. Using a like-gate is more than worth this drop-off, as the other 90%+ of non-fans who do like your Page will open a new avenue to market them again and again. (Wishpond)

Many app providers depended on the Like-gate as a major feature of their product. Banning Like-gates could directly impact their livelihoods. (Post Planner)

But, not to worry; since we’ve probably run more Like-Gated promotions than anyone, we’ve sifted through that data to let you know what to expect now that page policy prohibits requiring or even incentivizing for Likes. (woobox)