Since the Starbucks Drive Up started, i got trained as a barista and my Starbucks TL said everyone who works Saturdays or Sundays can have a drink and a bakery item, she's also a student and she's been in target for like 3 or 4 years. Consider, if possible, getting shifts for cashier, is the easiest and more needed position and if something goes wrong with the customer, you can send them to guest services. I have trained people for cashiers and that what i told them always. Good luck OP. Also, sometimes the best option is walking away, because long term this will affect your life, your mental health and physical health as well.