According to Osho, being in the front row means you're among the 'non-swimmers' - those who still need help crossing life's waters - while those not in the front row are the 'swimmers' who can manage on their own. It's a playful nudge: recognize your capacity; if you can't yet swim, admit it and receive guidance.
It means you're one of the people who can't 'swim' yet, so sit close to get help, while others farther back can swim by themselves.