Regulations are different everywhere. Read them for your area. Who cares what the fine is. Stay the f off private property without permission. If you don't know the status of the land you are about to access, stay off.
He never "pulled a shotgun". He had one in his possession though. Whats the problem? I'd do the same in this day and age. You never know what psycho may be out there on a sled or on anything that is trespassing on your land. This land owner is probably lucky he wasn't treated like that poor...