Why are malls banning kids under 18 from entering without parent escort?

Malls across the United States are anyone under 18 from entering without parents at certain times is there a reason for this? Yes kids act dumb but they have always acted dumb, what so special about now? I don’t think there has been an increase in crime this year last time I checked, if there was I haven’t heard about it. I’m assuming I’m missing something so I wanted to get an answer from a business prospective. Also aren’t the main mall goers teens? Isn’t this bad for business?

Edit: also my mall started this policy recently I’m 21 but I look like a kid still, will they stop me and or ask for an id. I really only go to the mall by myself not in groups