Violation of 5th Amendment priviliges
This product clearly violates US Constitutional provisions against Self Incrimination. Obviously, given the subject, I am an "Anonymous Coward" for 5th amendment reasons.
If this is used for entry into any building as a form of door lock, it will introduce a huge legal battle as the persons own sweat will make that person witness against themselves.
Companies that use this system will face all manner of lawsuits as in many cases, "drug testing" is supposed to be done under strict controls, many times including a distinct reason for the test such as accidents or other "Just Cause". Whose to say that the sweat from another person has not stayed on the fingerpint reader and becomes reactivated by the next innocent person? Where is the "due process of law"? Should there not be a big sign above the fingerprint reader stating that entry to this building may cause you to be busted or fired on the spot?
All the more reason to legalize marijuana and require specific quantitative tests that determine whether a person is "impaired" versus presence or absence of a drug. Right now the only testing is for presence or absence.
See 5th Amendment below:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offense to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.