At work I had paralleled parked about 75 feet from the office. The temperature was about 55 degrees out. I made sure to lock my car pushing the button and heard the sound. After a couple of hours (without taking the key out of my pocket) I forgot something in my car and went outside for it. The trunk was open slightly already. Luckily no one stole anything. Who knows how many hours it was open.

It's a matter that should be resolved asap especially when I am out shopping and if the trunk opens while I'm in a store, anyone could help themselves to whatever I have in the trunk.

Update from Jun 1, 2017: My husband had the extra set of Honda Civic key in his pocket along with other numerous keys. Since he specifically took out the Honda Civic key and put it in a drawer we have not had this problem since.