seat belt warning sound.

[Aybesea]

So after owning my Polo for 5 years the seat belt warning light decides to work,wondered what it was first of all when i first heard it then noticed the symbol showing.Need to know does it make the warning sound when the seat belts are not fitted or just the drivers.Or will sound till the engine runs.Hoping someone whose warning light/sound works,can help me with this.
Thanks.