A few brief responses. It was suggested that we should not compensate for loss of property, but only for humanitarian assistance. In some situations that is reasonable, but in otheres it would be misleading since property assistance and humaritarian assistance are sometimes hard to distinguish. For example, owners of small business may have all their wealth invested in property, or an elderly couple may own their home and nothing else. Property losses to these and other groups would be catastrophic too.
Perhaps the government could catalogue the risks in different locations. It would be a mighty undertaking however, since, for example, New Orleans on its past record did not seem very risky. But something along these lines is required if compulsory insurance is to be required in selected areas.
The Good Samaritan problem does not arise only when the compensation paid more or less fully offsets the loss. In past disasters, the federal government often paid victims a substantial, although still incomplete, part of their losses. Such victims would generally have their decisions affected even though they are not fully compensated for losses.
The poor of all colors and ethnicities do move across regions less than others. But over the years actually a very significant number of both poor white and African-American did move out of the South.
The strong emotional bond within many families cuts both ways. Parents may be more moved to help children in distress than governments are to help citizens, but at same time children may be more likely to refrain from bad behavior because they care about the effects on their parents.
I certainly do not oppose helping those enormously harmed by Katrina and other disasters. However, that does not mean that the Good Samaritan problem is unimportant, or that policies cannot make it less serious. Even if the choices of many persons are not altered by prospects of help if disasters strike, as long as significant numbers do look ahead, it is important to implement policies that push their decisions into more efficient directions. By implementing sensible public policies regarding disaster assistance, more resources would be available to help people truly in need.