The break in is sadly done by exploiting the weakness in a security feature, the emergency release latch. Without giving a whole lot of instruction, just know that a thief can insert a bent coat hanger from outside and catch the emergency release effectively unlocking your garage. How long does this take? About six seconds with skilled hands, made easier if you have stylish windows that allow the thief to watch his work.
Shown below is the emergency latch, know that this will vary from model to model. The latch is there in case of power loss during an emergency (such as a fire), and allows you to open the garage door by pulling the latch, disconnecting the door from the automatic opener, and lifting the door by hand.
Most, if not all, emergency latches have a small locking hole that allows you to run a small zip tie through and secure the latch. This creates too much resistance for a hanger and prevents the attack. When determining where to run your zip tie make sure you do not do it in such a way that it impedes the use of the garage door in normal circumstances and do not use a zip tie that is too thick to break easily when you pull the handle.
Once the zip tie is in place, make sure your garage door still works AND make sure to test the release latch. The latch should not work easily but you should be able to use a reasonable amount of force to break the zip tie and release the door. If the latch works without breaking the zip tie you need to inspect how you tied it down. Once you see it all works correctly, put a fresh zip tie in and sleep a bit easier.
You can see on my release I added the zip tie through the release pull so that it would have to be broken for the release to be pulled down. Well, I hope this helps you be more secure at home and tell those you know about this and keep them safe too.