My current car's trunk has two methods of entry:  An electronic switch near the steering wheel, and a keyed lock on the trunk door.  Most normal cars also have a latch on the back seat, but mine doesn't. 

A few months ago, my battery died due to the interior light being left on overnight.  What happens when a car has a dead battery?  The electronic trunk release button doesn't work.  What happens when you live in a cold climate with road salt and a seldom used keyed lock?  It seizes.  So in the middle of winter, with a dead battery, I was unable to get the jumper cables from my trunk because the idiots who designed my car couldn't envision a scenario where this series of events could happen. 

It wasn't a huge deal because I borrowed my wife's car to go to a store to buy jumper cables, which she needed anyway.  But if someone, perhaps a small child, got stuck in my trunk, I have a hard time imagining the success rate of convincing said child to follow my instructions in locating and operating the glow-in-the-dark emergency trunk release lever (which thankfully my car does have).