Most late-model cars (like this one) have remote trunk-opening levers near the driver's seat... If the passenger compartment is not locked, no key is needed for the trunk
This is a bad design as it turns any unlocked car into an unused refrigerator type thing
True. But these days to be a parent, you have to be paranoid, even if you think your kids are old enough, there always needs to be a grown-up watching them. I don't let my kids go around the neighborhood unless I am sure another parent is watching them.
Until this tragedy, I had never thought of that feature as a risk -- but, you are right!
OTOH, the latest models are supposed to include latch releases inside the trunk.
The truly sad thing is that most people don't know that the front of the luggage compartment (back of the rear seat) is notoriously weak on most cars. If you are ever locked in the trunk of a car, you can probably kick out the seat back -- and escape...