They don't have padlocks/keys on each individual person's stuff like they did for Step I or CK. Chicago CS center had basically a room with cubby holes large enough for you to stuff jackets+backpacks in.
The room is locked for the duration of the exam and effectively "sealed"
They do tell you to keep any cash you have on your person though (i think this is for liability reasons since it's hard to prove how much cash you had in your wallet, etc).
What i would do is zip up your backpack and just don't have the laptop out in front of anyone at the testing center -- people will figure its just books. And there's really not a time where anyone is allowed in that room without a proctor before or after the exam. So just keep your eyes open, and try and finish your survey at the end early so your stuff doesn't sit around too long (you go home after you're done with the survey).
