What is this supposed to do?

I’ve never been caught and have been shoplifting for over a year now but I always think my heart is going to stop whatever happens. My new anxiety has been messing with whatever I do so I wanted to know what is the point of those stickers they put on products. I just gonna say it’s liquor or meat or whatever. I thought they were for alarms or something but I was able to walk past the alarm 20 times after that whatever on the product is not even dead. What is the point of that?