A statement like that which is not part of the official decision are referred to as "dictum". Lower courts review higher court rulings, including dicta, and over time dicta has a way of becoming law.
Scalia is a kind of a Fourth Amendment hardliner when it comes to _the home_, so I'm actually surprised at this result. Fourth Amendment rights in so far as automobiles go have been eroding for years. Note that the concurring opinion wanted to reframe the issue such that there _was_ a reasonable expectation of privacy when it comes to automobiles (which would be a more expansive reading of Fourth Amendment rights).
Scalia is a kind of a Fourth Amendment hardliner when it comes to _the home_, so I'm actually surprised at this result. Fourth Amendment rights in so far as automobiles go have been eroding for years. Note that the concurring opinion wanted to reframe the issue such that there _was_ a reasonable expectation of privacy when it comes to automobiles (which would be a more expansive reading of Fourth Amendment rights).