My theroy is any day the so cal & so cal selects are not blocked will be busy. Last year i ahd the deluxe pass, but was able to go most saturdays. We went on the bats day weekend. Saturday was blocked for so cal and select passes (actaully all of august and most of july was.), but it was a great day in the park. We had several rides vechicles all to ourselves. It was kind of wierd being the only two people on pirates and nobody on the boats around us either. Anyway, sunday comes and the parks are sooo crowded. the first day so cal & selects can use their passes. Yes, I am aware it was also bats day, but not everyone lining up with their passes in hand were goth. I could not believe the difference in days. So, now I try to go when those passes are blocked...
(I'm not in the get rid of them crowd.)