1) A big concern with buying forclosed homes is that they are usually quitclaim deeds which contain no warranties such as seisin, quiet enjoyment, conveyance, general, etc.
2) Many people in California have been bailing on their mortgages since they default, lose their home (but it doesnt have any equity in it anyway) and then just take that loss as many states have anti deficiency statutes which dont allow for repossession of personal property.