Last night I watched a video on youtube submitted by a family of what I'm assuming are American tourists who took a self-guided tour of the walls. At one point they entered a locked gate when a local opened it to let them in. The mother joked about whether or not it was wise for them to enter, but they did, and later on the video they commented that an adjacent neighborhood looked "seedy". Fortunately they survived their tour.
The video:
http://www.youtube.com/watch?v=N5GIR7VSLfQ
It was with similar naivete that SS approached the walls and Z.
In another video a British tourist complained on video about the state of disrepair of the walls, and the lack of historic markers telling the events that happened in certain areas.
Tourists should be made aware of dangerous areas, but historic landmarks such as the wall should also be repaired and maintained. They should go from being considered dirty and dangerous, to a source of national pride. It would benefit Turkey's tourism industry, and also benefit future generations.
I may be overly idealistic, but in a perfect world the government might train the homeless and jobless, and create jobs for them repairing and restoring the walls and other national treasures.