Definitley animal, accident or mechanic, that's not how cutting brakes work. And have you ever dealt with wires,hoses,belts, or anything of the sort on a car? I find the idea someone can figure out the perfect way to slow delay cut that line, and have it guaranteed to work as intended without any affect from wear and tear, pressure, and other variables that could make the same type of line from the same manufacturer and material react differently to being cut all reacting the same to this one highly practiced cut( which means they either have done this multiple times or practiced, don't believe me you go cut this type of line and have cut just perfect) highly Laughable.