A potential thief can only speculate about the contents of any enclosed compartment (they might break in to find nothing), while they are sure there is something
in any visible container. That's an advantage, and the reason that police forces and insurance companies encourage people to put valuables away, such as in the trunk.
My hatchback cars have all had a removable cover over the area behind the seats. This isn't just for appearance, and it will clearly not prevent anyone from getting to cargo area contents once they are in the vehicle; it is there to hide any cargo so that thieves are not motivated to break into that vehicle to take what they can see.
Originally Posted by sturski
Many (okay, nearly all) of us tow with vehicles other than sedans or small hatchbacks, so we don't have a trunk or covered cargo area. On the other hand, there are usually small storage areas in which some things can be hidden... but rarely large enough for a laptop or SLR camera and gear. Maybe this is the best argument I've seen for towing with a Honda Ridgeline rather than more traditional pickups... it has that big enclosed box under the rear of the cargo floor.