But nobody was robbed. This guy looked in the house and then immediately called you to tell your door is open. Instead of thanking him, you sue him for trespassing. Technically, he would be guilty of trespassing.
Private residentce is a bad analogy. This is like being sued for trespassing because you stepped over a green-grey marble line on the grey-green marble floor of the open ground floor lobby of an office building where you work.