I am shocked that anyone would trust their 2FA to a slip of paper at an event where half of the crowd would probably describe themselves as a hacker or even social engineer.
There are either way more people who work in the facility than boxes, or nobody trusts that the cheap combo lock will work again when they need to retrieve their stuff at the end of the day. I've had to help a co-worker pry his box open and I was like, "why would you put your stuff in there?"
That same co-worker, by the way, later claimed that his ex-wife (or someone she hired) came to our facility and rooted his phone while it was sitting in our lobby next to the boxes. It turned out that he was deranged, but it made me think for the first time about the risks of everyone with a TS/SCI clearance predictably leaving a big pile of phones unattended.
(Fyi, you can always spot the secret squirrels by their watch tans. Only those who work in places where cellphones are not allowed still wear wristwatches 24/7.)