How do you know if your storage unit has been burglarized?

An employee like myself will alert you that your storage unit was missing a lock after you discover your lock has been replaced with a painted red lock though it doesn't matter because all your valuables are now gone and in the hands of the criminals (my friends) that I helped during the burglary

There will be a red dummy lock on your storage unit instead of the lock that you put on door. And then you'll know. When my storage unit was ransacked, I counted more than a dozen red locks in my hallway alone. These thieves don't worry about being caught. They take their time. They know they can rummage through your unit all night long. And they do. Don't rent storage here. Your stuff will be stolen. These are horrible people and criminals. You've been warned.