If one is planning to propose here do they need to get special permission ?

No permit, just do it! I did it and she is still raving about it. Congrats and good luck

No. It's a public place. If you are planning a special event that requires sole access then yes, you need a permit. But, if it is a proposal only amongst the other people, then you're okay. If you need a photographer, check out thetanzipaparazzi.com