I work for Asda on checkouts/customer services and I can tell you that the checkout staff is fully trained on security. The checkout operator was cleary neglecting her job in this case. THE ALARM CAN NOT BE DE-ACTIVATED and can only be removed using a special magnet on checkouts (i tried my own magnet and did not work - maybe might work for you). If the alarm made no beeping noise on the checkouts it means the checkout supervisor did not turn on the alarm system on checkouts using the alarm key. Each checkout has a seperate alarm system lock undernath the checkouts. The best thing to do if this happenes to you is to take the product back to store with reciept. Also the home and leisure department is utterly rubbish in the store I work so this might also be the case in your store. As for alarm sounding through the door it is NOTHING TO BE EMBARSSED ABOUT.