As the conference nears opening day on August 1st, this move by DEF CON organizers eliminates any speculation about the possibility of the NSA participating in the hacker conference, and raises questions about what feds might encounter should they decide to attend DEF CON anyway.
The no-feds-allowed caution is ominous in light of recent world events.
As hackers and feds alike prep for Vegas, the world still reels from recent NSA/Prism revelations of extensive digital mass-surveillance on citizens worldwide, from information leaked to UK press by former fed Edward Snowden.
Just last week, a Federal judge gave the EFF a crucial winning point in its lawsuit against the government's illegal dragnet surveillance programs when the judge rejected the U.S. government's invocation of the state secrets privilege to have the EFF's case dismissed.
With this new development, this will certainly be one of the most interesting DEF CONs to date.