Well, over here the two types of accidents are the one where a farmer is pulling trees and the wire snaps and hits someone. If the wire dont snap sometimes the tractor falls over backwards and squashes someone. Last year one guy got about half of his teeth knocked out from a flying pulley.
The other common accident is the classic snow blower one. Snow is blocked in the inlet and the farmer puts hits soon to be ex foot in the hole to kick some snow.
A whistle is a good thing to have tractor or not. A knife is a good to have thing too.
So if you are using heavy machinery, a knife like a KaBar Warthog is the thing. A Fallkniven F1, Strider something or any other 3-4" knife that is strong enough to dig with but not too bulky to carry around is great.
I can see a new line of tools emerging. Something like the Strider BD with a John Deere logo on it and green all over. A PSRTROK for every tractor brand, for different climates and so on. "Show that you care for your farmer friends, get them a PSRTROK today" Now with free engraving. Order now and get it before the harvest festival.
I hope that farm guy framed his knife and bought himself a whistle and a bigger knife.