I've spoken to several first-responders in my life and NONE of them carry a knife to cut people loose from a seat belts. Instead, they carry strap-cutters. The reason is, accident victims can panic and become hysterical at any moment and start jerking around and/or flailing their arms. They can also be suffering from brain injuries that can make them uncontrollably violent, even violent towards those who are trying to save them. Using a knife around such people is asking for trouble, like injuries to the victim, the responder, and maybe even a lawsuit.
Although knives can be useful, I would suggest that you recommend to your friend that they get a strap-cutter.
Of course, I would assume that there are specific guidelines for volunteer firefighters, like maybe a manual or something. I would assume that they have to take classes, etc. If your friend hasn't been told by his superiors what equipment he needs to acquire for himself, I think it would be a good idea for him to ask his superiors. I would imagine that if there is some sort of injury resulting from a firefighter using an unauthorized piece of equipment, that the department, and the city/county could be sued.
