Binary option scams and fake binary option brokers have deals that are too good to be true. Their headlines are always catchy, luring a lot of people into sending lots of money without any plans of making money for you. Also, the trader is always pushy to make a deposit so business can start, but they just keep asking for more and more showing you what you want to see, their mostly used tactic is greed.
Also, once you have made a deposit without confirming the authenticity of the broker, you can ask for a withdrawal and see how that goes, which is the final red flag of knowing if you have been scammed.