Person In Charge

I had to return something at Safeway yesterday, and the man behind the customer service desk had a nametag that said: "Trevor McSpadden - Person In Charge." I'm thinking the logic behind that kind of job title is that when some crazy lady decides she's going to throw a fit and demands to speak to someone in charge, they can bypass this kind of conversation:

Lady: "I demand to speak to someone in charge!"
Trevor: "That's me, ma'am. I'm the Assistant Shift Supervisor."
Lady: "Whatever! You're not really in charge! I want to speak to the manager!"
Trevor: "Well you see, I actually am the right person to talk to because at Safeway the manager on-duty is given the illustrious title of Assistant Shift Supervisor, so I am functioning as a manager while the real manager isn't on site. I assure you that I am fully capable of assisting you, even if I’m not the real manager.""
Lady: "Whatever! You're not really in charge! I want to speak to the manager!"

...and move right on to this conversation:

Lady: "I demand to speak to someone in charge!"
Trevor: "That's me, ma'am. As you can see on my name tag, I am the Person In Charge."
Lady: "Oh good, you'll be able to help me."