when does it cross the line?

I have been reading about disaster photography and came across a lot of interesting forums and blogs. It made me think how much is too much? if you think when a disaster strikes most major newspapers and magazines send out various photographers to the location and it makes you think people are in crisis do they really want loads of photographers taking photo's of them in distress and when does it cross the line on what you can photograph? 

http://www.npr.org/blogs/tellmemore/2010/01/disaster_photography_when_does.html