All attendees must be 18 years of age or older to be on the conference floor. Attendees must wear badges at all times in the conference areas. Badges and/or conference proceedings that are lost or reported stolen will incur a $500 replacement fee. Note that this schedule is subject to change. All attendees are required to wear badges and conference proceedings at the conference. The fee is $1,000 per person or $500 per person for any lost or stolen badge or conference proceedings.”]
Source: https://blackhat.com/html/bh-dc-07/bh-dc-07-schedule.html