I worked for a certain large corporation at one time which had a mandatory piss test before you could be hired (which many do have). The board then had the bright idea of repeating that test for every single employee every year, who knows why. Some perceived drug problem or making points with the government (they do have government contracts), don't know.
After the first year, an announcement came out that the "program" would cover the entire employee population only every 2 years. Then, after about 3 years or so, the whole program quietly disappeared - no announcement. No doubt, there were so few if any positives and/or the cost was getting to be too much.
Unfortunately for the Florida case, government is involved, which is usually oblivious to cost. That money could be used more productively for the schools.