Security officers cannot rely on another person s word that a misdemeanor crime occurred. So this whole business of stopping a person for rule violation, transporting them to the mall security office for processing, and formally trespassing them is improper. Also, improper is requiring mall miscreants to stand in place while security officers obtain ID, bring forms and a camera to photograph them before issuing the trespass warning. To argue that the offending teenager volunteered to be detained for the purpose of being trespassed and processed is risky and should not be practiced. There are many exceptions like when trespassed teenagers return with their parents.
Good judgment is key.
However, here are times when detention and arrest of criminals and trespassers is proper. Legitimate troublemakers and known criminals who have been trespassed previously sometimes should be arrested. The mall has an obligation to keep the premises reasonable safe. If mall security learns that a previously trespassed person has returned it can create a liability, especially if the person is known to be potentially dangerous. If the person previously trespassed is not believed to be dangerous then discretion can be applied, depending on mall policy.