I don't have to take my shoes off airports. A govt contractor looked at my birth certificate and driver's license and charged me $78, and then gave me a special

I don't have to take my shoes off airports. A govt contractor looked at my birth certificate and driver's license and charged me $78, and then gave me a special number to put on my boarding pass. Now a man at security gives me a little red flag that says I don't have to take my shoes off. Honestly, I don't know why everyone doesn't pay for TSA PreCheck and GlobalEntry.