What happens if a player misses submitting his picks for one of the tournaments? How does it affect his/her chances of winning the season cumulative competition?

If you are basing your standings on total strokes, players without picks for a tournament will be listed as such in the cumulative report and must be ineligible to win the season long competition (their strokes will be significantly lower than everyone elses).

If you are basing the standings on winnings, then they are still eligible as they will simply have $0 for the missed tournament.

NOTE: Depending on your pool rules, the commissioner can always enter picks for someone after the deadline by going to Commissioner Console --> Member Pick Maintenance