Most of us have jobs and its hard to get more than 2 people out on a given day. I thought that was part of it? Make it practical?
Making 75% of team members sail to validate a session would exclude a good portion of the teams. Might give the dole bludgers and retirees a chance though

Reasons for best 2 scores is:
1) It doesn't favour smaller teams
2) It doesn't discourage the slower guys on the day to post
3) Nobody knows who is going to be fastest in all disciplines (well chosen BTW), until the data has been posted. Creates thrill and excitement etc and motivates guys to have a go (eg at least for the 1 hour, total distance, or alpha rankings)
4) The bigger the team the better the chances, which encourages team playing!
Reasons against:
1) A few guys might think that their slower team members ~might~ be upset at not feeling included. hmmmm anybody asked them?
As someone who was not in the fastest 2 in some divisions, I'D BE PROUD OF MY TEAMMATES FOR STEPPING UP AND DELIVERING THE GOODS. And I might not have posted FOR THE GOOD OF THE TEAM.
If you average all the scores, the smaller teams are statistically favoured. So its a bit flawed. If you take the best 2 scores from each discipline, it favours bigger teams. Isn't what this is about??? Encouraging team spirit?