I've also noticed if you press the lock button on the remote when the car is already locked, the alarm goes off.
It is called a panic button in the USA.
A lot of people use it to find there cars also, when parked in HUGE car parks etc.
Hitting the lock button, will sound the cars horn and flash the lights on some cars in the USA.
On the ZS EV - If you have not correctly closed one of the doors and you try locking the car, it will sound the horn once to let you know something is not 100% correct.
Also, if you place the car in "N" and hit the "P" button, then jump out BEFORE shutting down the car correctly, it will not allow you to lock the car with the remote or the button on the door.
Ask my how I know !.
Last week, I had to make a very quick pit stop at the local chemist to pick up some urgent med's for somebody.
So, I pulled up right outside the chemist and selected "N" and pressed the "P" button.
I though I had hit the "STOP" button, but I don't think I pressed it correctly, as I was starting to leave the car at the very same time ( we all know this one.)
I could not understand why the door mirrors had not folded or why the car would not lock ?.
When I opened the drivers door again, I could see that the car was still powered up - DOOH !.