It is NOT illegal to take normal photos on the MTR. When you're in a public place you give up your "right" to privacy and can be legally photographed (as long as you're not on private property which explicitly prohibits it). However, taking a normal photo is very different than voyeuristic praying on underage girls. Additionally, the photos taken in public, cannot be used for commercial purposes (i.e. advertising) without obtaining a model release of any "recognizable" person in the image. They can however be used in artistic shots and be sold as Art.
For example....this is not illegal:
Flickr ?? Travel [email protected]@[email protected]@http://farm3.static.flickr.com/2659/[email protected]@[email protected]@[email protected] @[email protected]@06a4097959