Criminal Appeal goes over a decision wherein California holds that the government's interests outweigh a person's right to privacy if he is on probation even if there is absolutely no individualized suspicion. Therefore, DNA can be taken in order to develop evidence for cases which happened before and after the person was under the legal supervision of the courts and probation.
Posts: here - here - here - here.
[comment] The problem here is that the government's interest will always outweigh the interest of the individual - in each and every situation. It's the reason balancing tests are so very dangerous to our rights.