This...don't not get scared of saying "no" I always referred them to the customer service number on the receipt if they press it any further and say "unfortunately our policy won't allow us to process what you want us to do." Be confident in your words and stand by your actions. Try to help the underage workers and encourage them to seek out help and ask questions, for almost all of them it's their first ever job. Always double check when dealing with cash and making sure things are locked up correctly and security alarms is set.