a member of the family has a audi a3 1.6 sport around 2000 plate i think it is. one like in the link below
hope i am in the right section but i am not clued up on audis.

basically what happens when the car is locked and left for a while
the hazards are turning themselves on, flashing thru the night or time period then draining the battery so that is flat.

is there any common or likely causes for this and anything i could repair/replace to stop the hazards coming on and draining the battery?
i think they must be coming on when locking the car by remote then just continuing to flash but my family member hasnt noticed.

any help much appreciated!
thanks in advance