Yes, it really can be that simple.
Did you know that there are people who travel through neighborhoods in the middle of the night checking door handles on cars parked outside just to see if they're unlocked. In many cases they are, and in these unlocked vehicles are various electronics, GPS devices, phones, purses, wallets, and the list goes on and on.
Inside some of these unlocked vehicles you'll also find garage door openers that will allow thieves to gain access to the inside of your garage where your other vehicles are, or worse yet, the inside of your home. Leaving a garage door opener inside an unlocked car can be an open invitation to enter your house.
In 2013, the Overland Park Police Department took 298 auto burglary reports involving unlocked vehicles. That number is about half of all the auto burglaries. Just think of how much lower the total would be for the year if the owners had taken the time to secure their vehicles.
The majority of these thieves don't want to take the chance of waking up the neighborhood by breaking a window, hoping they'll find something of value inside - because there's too many other vehicles down the road that may be unlocked.
The simple solution is obvious in order to reduce the majority of these "crimes of opportunity." Lock it up and don't leave valuables inside!