I want to take this a step further. What if they show up at your place of business, which you own and has a variety of "thresholds"?
That still doesn't answer the question..
I have three thresholds in my house. And the garage / barn - which is NOT attached to the house - has five - if you include the garage doors.
Seriously - is the actual law that vague that nobody can answer this question other than a lawyer?