I hunt deer alone almost all of the time.
I hunt pigs alone depending on what ranch I'm hunting, but I always let the closest person to where I'm gonna be know so that if they haven't heard from me then they can come looking. (I've got a record with gettin charged by the darn things)
And I always sheep hunt with my dad, mostly because it's all rugged canyons with no cell phone coverage and it just doesn't make sense for me to go alone especially when he wants to go along to.