Like many of other window cleaners, I use the 6" razors almost daily. In 25 years I have only had one employee cut himself enough to need the ER. It also happened once to me when a rustic piece of decorative wood frame came loose and jammed the razor into my thumb.
After the incident with my employee, it made me consider what would happen if it had been a major artery and no one was around to help. Since then I have always kept at least one Tourniquet in each vehicle. They are cheap and easy to find online or at medical supply stores.
Hopefully we will never really need to use these but I have peace of mind knowing they are there. We keep them in a place that is in open view and quickly available in the event of an emergency so a person could easily access it and stop major bleeding until help could arrive.