This is NOT for Enforcement Purposes (Score 4, Insightful)

This is by no means new. The purpose of these tests is to track usage patterns. Such patterns are useful for understanding how and when drug usage trends spread from city to city, in addition to usage patterns over the course of a week or month. It is totally inconceivable that these tests could be used to identify drug users. Even if it were technologically possible, the cost would be prohibitive. If you could arrest every current drug user for possession, we would have many, many million more criminals than our jails could hold, not to mention the fact that jailing drug users is an excessively harmful way to deal with what is really a health problem.