Most trespass laws require you to tell the person to leave before the law kicks in. It is hard to find a trespass law that is a felony. Most are minor crimes. Some will claim they have a law allowing lethal force to protect property or prevent trespass. Besides, shooting someone for trespass or a property crime is rather silly and not wise.
Drunks frequently walk into wrong apartments, or the wrong house.
Again, it is not worth shooting someone for that. They can wander in at any hour. Drunks and those with mental problems have little respect for time. This is where they just walk in and take what they want and leave. The gun community has taken a beating when gun owners have shot friends or family members thinking they were intruders.