We have used In N' Out for decades for the Rose Parade. We virtually feed every participant in the parade, including each and every band member, equestrian units, and float riders. We also feed the players on Press Day and the participating bands in Bandfest. I had the honor of helping to negotiate a meal price when I was on the Food Services Committee. In N' Out brings multiple vehicles out and sets up a small compound. You wouldn't believe how many burgers they can produce in an hour. For these various engagements we have potato chips and no fries. We also have them include an apple and a soft drink. The parade participants only receive a hamburger or a cheeseburger. The participating football players in the Rose Bowl Game are each allowed two double doubles on Press Day (not the same day of the game). Back in the mid 90's our negotiate price was $1.70 per meal. While we still use In N' Out, I haven't been back on that committee for quite some time.
My office building also hires out In N' Out once a year during summer to serve burgers to each and every person in the building (14 floors). We are allowed a double double, fries, and a soft drink of our choice.