Up untill now I was convinced that the beeping is completely random.

 

Mine beeps. I made it beep. It is very simple.
Open the center console. Look down at the latch. You will see a flat metal piece. It is part off the switch that tells the alarm that center console is closed. Take a small screwdriver and push the metal piece further down. Now you horn will beep everytime you lock it. The downside is the center console is no longer monitored. So it would not be a good idea for a cab.

 

I can hear my doors lock if I am near the car... I can also hear the light flash solenoid to blink the lights if I am close. I just got in the habit of locking the car when I am close to it.