I agree that if someone wants to get in to steal your stuff, they will find a way! However, throwing any impediments (like the box) in their way adds complication. Also, not having items visible is a plus.
This box was one of the first things that I purchased when I bought my truck. I really love it! Months after I installed it I happened upon the Lock'Er Down Item #LD3025 which looks much safer BUT at $950.00 it didn't seem worth the cost!
As for installation, as someone above said, it was a breeze! I did replace the back floor mat with the Husky Second Seat Footwell coverage and it works great!