Why Is This Rule Made?

Many questions that students have is "why are we not allowed to go in at once?"because of some students/teens that have done many problems like for example shoplifting this gives the store owners the prediction of some student that will shoplift.yes some teens/students might shoplift but not all do.when one does something bad it effects the others because they would face many of the consequences such as the rule that some stores have now a days