> The same action of another can result in my car being stolen whether I leave it locked or unlocked.
Taking advantage of a car being unlocked involves completely different actions than with a locked car, so no, not at all. (And as far as stealing the car goes, a non-hack involves leaving the keys in it too.)
If you walked through an open door to steal something, it won't be "breaking and entering" either.
It would be burgulary instead of breaking and entering. You still get charged, just like accessing a computer unlawfully doesn't have to involve clever tricks to be illegal.
That’s criminal trespass. Accessing something not yours, when the owner has some expectation of you not accessing it, even if easy to do, is often illegal.
Owners not locking goods down does not give another the right to access.
Taking advantage of a car being unlocked involves completely different actions than with a locked car, so no, not at all. (And as far as stealing the car goes, a non-hack involves leaving the keys in it too.)
If you walked through an open door to steal something, it won't be "breaking and entering" either.