What are your thoughts on random drug screening?

Whether it’s an insurance reqirement for a business or a cop issuing a breathalyzer after a wreck….Do you think it is a violation of our Constitutional rights?
I have a former classmate who is rabid about this issue, claiming all of the above.
I disagree. I think people deserve the reassurance that the people who have access to all your finances aren’t under the influence, or your coworker driving a forklift next to you, or your medical providers or waiters and waitresses.
And if a drunk driver hurts someone you love they should pay.