[kpugh]

From FIRST's website Re: championship eligibility criteria:
"For 2004 and beyond, a select number of Championship spots each year will be available for open registration. These slots will be based on the number of years since a team last attended the Championship. All teams will be classified in a Tier (ie. Tier 6 equals six years since attending a Championship or last attended in 1998; Tier 2 equals two years since attending or attended in 2002). If the number of teams in a tier is greater than the number of available slots, FIRST will use a lottery system for teams within each tier to determine eligibility for the remaining open slots. The final determination will be first come/first serve until all available openings are filled. A wait list will be maintained for any openings that become available after the close of registration. Typically 10 to 15 openings occur during the Competition season."

My guess is that after all interested teams from Tiers 6-2 signed up there are still spots left in the championship event. Since more teams are in Tier 1 than there are slots available, they did a random lottery to see who would be eligible to attend.