It's important to remind kids that in the excitement bikes disappear rather quickly, especially later in the weekend. "______ is watching my bike" can lead to problems as ____ is distracted in the excitement.
Also, don't lock a bike to a door, regardless of the door being locked/closed or not: Security will cut the lock. It sounds simple, but every year somebody's lock gets cut. I usually just lock up in the ABA lockup upstairs and forget about it.
Something soft to sit on, and something to entertain oneself over the course of a 1,000 moto day. A book, an MP3 player, and a chair so you can take a break from the bleachers are all good.
Sharpies so you can get autographs.
Cash so you can take advantage of the deals. Snacks because the snack bars don't make deals.
Saline spray, yes, keep a second bottle in the shower at the hotel to help sinus clearing. (Me, I'm a big fan of the Netti Pot, a big fan. Walgreens has a plastic one that's great for travel).