Has anyone done a "walk up" dolphin swim at DC

[Hemlock]

I am contemplating added a visit to Discovery Cove for our May 2011 trip (mostly based on the awesome reviews that I have read here). We are already booked pretty tight for our holiday, so I was thinking of deciding once we are in Orlando if we feel up to it (maybe 1-2 days before or possibly the day of). Has anyone ever arrived at park opening and booked a dolphin swim or does this absolutely require advance booking?

 

[chiamarie]

Advance booking. Maybe, if your lucky and someone cancels; you might be able to get their spot. But from spring break and through summer it does require advanced booking just to get a spot in the park!