Just be careful if you are working with someone, or even by yourself, if a combine was bolted onto a factory floor there would be all sorts of lock out/tag out stuff all over it, for doing maintenance... Farmers just have to be careful!
I may have almost baled my buddy one day, we had unclogged the round baler pickup and I went back up onto tractor, and saw him start walking back to the truck, but he noticed that the twine feeder had some extra flopping around so he went back to the front of the baler, and I had my foot over the forward pedal, and was about to hit the pto button but fortunately I looked back... Probably he would've been clear of everything, if I started the baler, probably....
But it sure makes me think now, and that's as close a call as I want to have.