In a former career, law enforcement, yep, a number of knife incidents, though not like employer-employee stuff but more like people you were arresting having knives concealed in unusual places. That was a time in my state when there were carry and blade length restrictions, which have since been repealed, so knife carriers could potentially be charged with a crime.
The most amusing was this old drunk carnie (literally, a carnival worker) who another officer had arrested for being drunk. This guy had like an 8" butcher knife tied by a loop of string to his belt, hanging down inside his pants leg. The arresting officer had missed it during a pat-down (the guy was a really nasty stinky old drunk - you would not have wanted to pat down the guy's pants either) but the jailer found it during the intake search. I was in there with my partner at the time processing a different arrestee.
Guy claimed that his job was to run the "guess your weight" attraction where you win some cheap prize if he's wrong. My partner said "Ok, guess my weight!" The guy said something like "160" - my partner was a big guy and weighed about 220. He said "Man, you're way off!" The guy comes back with "Well take your damn prize". We laughed our asses off.
In my current situation, my work place is my home, so no incidents.
When I was still working from an office with my current employer (regular corporate gig, not law enforcement), the facility I work in has metal detectors and a no-weapons policy. I do occasionally need tools and am considered somewhat exempt, so I keep a couple of Leatherman tools and a small SAK in my bag, but mainly for the screwdrivers and pliers.
About a decade ago a person for whom I was fixing a computer was looking askance at my Leatherman Juice - I was using it as pliers and screwdriver - and actually commented about me not being allowed to have it. The person was a contractor, not even an employee of the company (I am), and I was using it to fix a problem SHE HAD CALLED ABOUT, which was part of my job at the time. Nothing ever came of it, but it is amazing the types of things people have been conditioned to be sensitive to.