You never know when "Management" might do some random testing. If the workers compensation provider puts pressure on the company to do so, like if there were an abnormal amount of claims compared to competitors in the security business.

I have the same knee issue's you describe, since my teenage years. Been to all types of Doc's and no resolution except MMJ. I also have the burning sensations in my feet and knee's. I am subject to random testing and if injured at work its an automatic test if you receive medical attention other than a band aid. So I am always looking for a different work environment.