Might disaster relief fatigue be starting to set in?

Just before traveling to Sichuan yesterday, I had a conversation with a friend in Shanghai who said his parents—both retired—had been asked by the management at the apartment compound they live in to donate to a fund that fellow residents were putting together. They did so happily. Then, a couple of days later, the father was asked to donate to a fund that his former company (state owned) was putting together. Again, sure, no problem. After that his mother, a former school teacher, was also asked to donate to a fund that her old school was collecting.
My friend was a little uncomfortable saying it, but he conceded that when they were asked to donate for a third time, they were “a little annoyed.” (The parents in this case are anything but wealthy and felt they had donated fairly generously already).
I wonder if similar feelings are at all widespread, or whether the three-peat in terms of requests for their contribution is just an unusual case?