That's normal, cuz when your lock screen is password protected, if you tap let's say Wi-Fi, it will toggle the wifi, but if you tap it twice (double tap), it should be getting you to the Wi-Fi settings, but since your screen is pass protected it will ask you for the password. Same goes for Bluetooth, Camera and Rotation Lock, cuz they are quick toggles, they don't go deeper than that.
Alternatively you can switch that off from settings, so the only time you can swipe down the Notification Center is when your device is unlocked. Hope I made it clear, cuz i was about to go to sleep and i am very sleepy atm, but i saw your question and had to answer you.