During the session, Agent Jim Christy of the Defense Department's Cyber Crime Center asked the audience to stand.
"If you've never broken the law, sit down," he said. Many sat down immediately - but a large number appeared to hesitate before everyone eventually took their seats.
OK, now we can turn off the cameras, Christy joked.
Some federal agents were indeed taking careful notes, though, when researcher Michael Lynn set the tone for the conference by publicizing earlier in the week a vulnerability in Cisco routers that he said could allow hackers to virtually shut down the Internet.
Lynn and other researchers at Internet Security Systems had discovered a way of exploiting a Cisco software vulnerability in order to seize control of a router. That flaw was patched in April, but Lynn showed that Cisco hadn't quite finished the repair job - that the same technique could be used to exploit other vulnerabilities in Cisco routers.
Cisco and ISS went to court to try to stop Lynn from going public, but Lynn quit ISS and spoke anyway. In the wake of his decision, Lynn has become the subject of an FBI probe, said his attorney Jennifer Granick.
Many at the conference praised Lynn.
"We're never going to secure the Net if we don't air and criticize vulnerabilities," said David Cowan, a managing partner at venture capital firm Bessemer Venture Partners.
And the vulnerabilities are plenty.
During his session on ATM machines, Morris said thieves have been able to dupe people out of their bank cards and passwords by changing the software in old ATM machines bought off eBay for as little as $1,000 and placing the machines out in public venues.