Ok so ya just shot a dude, right? Then you tamper with evidence/crime scene (removing shell casings), and don't report it. No one's around, right? Except maybe the hunter's game camera hidden in a bush that caught the whole thing, but from the wrong angle... or the guy's not
quite dead... and the hikers a few hundred yards off who heard the gunshots come to investigate, they call the medics with their lil sat phone/local beacon thingy, maybe the badguy survives.... or maybe once someone random comes along and finds the dude, calls it in, they put Gil Grissom on the case, so now your ass is really grass
Yeah man I'm playing devils advocate here. Saying nothing is bad, trying to cover it up even worse... and even if you NEVER get caught... you have to live the rest of your life with that little seed of "what if" in the back of your head... every time someone knocks on the door, every time a cop looks your way, tickles that lil seed... that kinda thing could drive a man mad.