McDonalds doesn't teach queueing theory

I was in McDonalds today (don't ask), and there was a single line in front of the one attended register. One of the staff opened a second register, but everyone happily stayed in one line. Here's the dialogue that followed:

McDonalds : "Please form a second line here"

Steve : "Why?"

McDonalds : "What?"

Steve : "Why should we form two queues, when one queue is more efficient?"

McDonalds : after 3 or 4 second pause, "Because I say to"

Can't argue with logic like that....