I had this happen while I had stuff in my trunk. I went around a corner too fast and as usual I heard a thud. When I got to where I was going I noticed the door open light was on. Turns out my stuff slammed into that lock button thing in the trunk and it opened somehow? Either that or the strap from my bag wrapped around the emergency release strap on the latch and it opened it as a turned and slid and hit the lock button on the wall! anyways I wish there was a cargo net or something that came with the car. I keep beating up my trunk by corning to hard.. I guess I need to start practicing with the water cup in my cup holder