The line-up is long. All of a sudden the store alarm goes off - and then this little voice tells the room that the cashier forgot to de-magnitize the protective tags. The couple goes back to the cashier and she swipes it through again to fix it. No big deal, this happens to me all the time. So we keep waiting in line.
Next person goes. Same thing. Mum turns to me and says, "must be a new employee." Next person goes. Alarm goes off and that little voice. Goes back and swipes it through again. By this time the other people in line are getting cranky.
A few more people go, and the alarm chirps merrily away. Of course we also get beeped by the alarm, and have to go back for the cashier to de-magnitize it again. As we leave the store for real, we hear the alarm go off behind us again and that cheerful little voice reminding the cashier to fix the tags.
It's probably not going to get the employee fired, but for goodness' sake...how many alarms will it take before you realize you're doing it wrong?