Secured or not, they realy should not be taking anything remotely private into a hacker convention. Certainly a laptop as you have said that is wiped after it is image dumped and compared with how it left to identify any possible new threats that poked there way onto it whilst there. Then popped into a cupboard after reimaging ready for next time. Reimaged from external DVD/blueray discs to eliminate any bios cleverness that may or may not infect a imaging server, trust nothing remember.
The only data that should ever be on a laptop at such places is test/madeup data that you want leaked to see how the water flows so to speak.
Security is only an illusion at a point in time, whats secure today is not garanteed secure tomorrow and with that was not secure when it was secure, also easier on the brain when you can just remove the security by making it a non issue.