fwiw, my niece went to French Polynesia in April. She bought a walk up fare to Moorea. The counter agents wouldn't even discuss selling her a ticket for an hour or so after she arrived at the counter. They were too busy processing those who had already bought tickets, and checking them in for their flights. She is young and not an experienced traveler, and it was very unclear what they were meant to do. Finally, someone came from the back and sold them their ticket.

Based on her experience, I've decided to buy my BOB ticket in advance for travel later this year.