Event Leaderboard Mechanics
It looks like the event leaderboard is a random selection of people at your current level. I was already 5th place this morning not having done anything, and the people displayed were definitely not on my friend's list.
If the above is true, then perhaps it's more strategic to be at say Level 32 or 31 instead of 33 or 25 (being the most common levels) so there's much more competition for prizes. Apparently some people have no one else on their leaderboards also.
Can anyone Level 34 or higher confirm if the leaderboards are empty or near empty?
Also do the pirate enemies for the event match your current level or are they all level 33?