You can show up during the event, sign the log, pose for a group photo at 12:30, trade and discover trackables, and earn your leap day souvenir. No need to give notice that you're attending, and I won't require you to stay longer than it takes to sign the log.
There is free three-hour parking behind the library. You can enter the McConnell Center at Door 2, go down the stairs, around the corner to your left, and find me at a table near the windows. If you are on the other side of the building or want handicapped access, you can enter at Door 7, and just walk straight ahead into the cafeteria area. Or hidden Door 8 brings you down the steps right into the cafeteria area. Entering by any other door into the building might lead you in circles, but not to the cafeteria.