I have analyzed and reviewed a lot of insurance policies. I have never seen one that has a (special, or any, for that matter) exclusion for knives, guns, whatever. if you are referring to worker's compensation, the coverage must follow statutory law (in the US) or USL & Harborworkers/maritime/Jones Act for offshore and those do not exclude knives, etc. So there can be safety reasons, but citing insurance as the reason is bogus.