In the distant future, a multinational corporation has become more powerful than any government. To deal with individual enemies of the corporation, the company created the enforcer line which specializes in robot->human combat.
The enforcers pack a variety of weapons and gadgets but the most terrifying of all is the DNA-EYE. As people live, breath, move, and interact with their environment they release skin cells, hair, and other cells. The DNA-EYE is acutely aware of human cells and will use X-ray scattering to identify the gene sequence of the human who left the cells behind. Thus it can connect the cells to the person who left them as a unique identifier. The cells left behind last in the environment for some time and so the DNA-EYE gives the enforcers the ability to track targets for long periods before eventually catching them and dealing with them. It only needs a single cell for identification.
My questions are:
Would this be a viable method of tracking? Do we release enough skin cells often enough that the robot can simply follow the DNA trails?
How long does the DNA remain viable after it has separated from the human body? Does it depend on what type of cells the DNA is in?
What might someone do to prevent being tracked this way? Would covering yourself from head to heel in cloths be enough to cover your tracks? I think an astronaut suit would probably suffice to hold in your DNA, but what else could be done? If you use one of those showering stones to remove dead skin would that stop the shedding?