I don't know about lunch, but the last few years that we've stayed at the beach club villas we've wandered over to the yacht club galley for breakfast and we've never had a reservation - probably never waited more than 10 minutes for a table.
Of course, we usually visit in October when the crowds are a bit lighter.
They have a great breakfast buffet at this restaurant, but I always order the giant mickey waffle. Yummie! Can't wait to get back there this year!