I worked for them once. We had a kitchen fire while preparing the store to open, about 5am. McDonald's brought in a crash team of people that worked with the fire department, insurance adjusters, cleanup workers, and health inspectors to get that store back into shape to open...at 7pm THAT NIGHT. On a SUNDAY. That's how serious lost business is.
I have a general rule not to visit a new restaurant for the first two weeks because of this exact same "meltdown" scenario.
[Little known unpublished McDonald's fact: Not sure if it's still true, but at one time they honored all competitors coupons. Yes, they'd give you a free Big Mac with a free Whopper coupon.]
[And yeah the coupon thing is still there. I once spent half an hour arguing with a woman who knew about this fact and was trying to convince me a free Strawberry Shake was equivalent to a free Slurpee coupon she was holding. Had to say no to that one.]