http://miceage.micechat.com/allutz/al030212a.htm

I am shocked the Disneyland was that unprepared for this. Luckily they were able to survive and have a good business night.

66,000 annual passholders and 40,000 non-passholders visited either one or both of the parks that day.

That's precisely where the problem was.

I'd imagine that a very large chunk of the people who visited Florida's event were there by chance. Like many visitors to Walt Disney World, they'd probably booked their trips last fall or earlier and just decided to take part since they were there. There was certainly a tourist component, too, but the two month turnaround between the event's announcement and Leap Day really isn't even enough time for people to plan a trip to Orlando.

Disneyland is much more a regional destination for many, and with the dirt-cheap Southern California passes (none of which were blocked out), people descended like flies after work and school let out. Not to mention, social media played a part here and it wasn't always good. Search "Disneyland rave" on Twitter and you'll find that a number of young people had gathered in Tomorrowland where firsthand stories say inappropriate language and illegal drugs overwhelmed Disney's security force. Allegedly, people began noticing the topic trending in LA and pass-holding teenagers and twenty-somethings flocked to the park in response.

EDIT: This is also why rumors persist that Disneyland in particular is looking at how to change their pass policies and stagger ticket prices to make "park-hopping" more difficult. At Disney World, it's not entirely realistic to "park hop" all day long since boats, monorails, and busses separate the parks. At Disneyland, folks walk right from Disneyland Park to Disney California Adventure. The worst part is that when DCA closes at 8:00, probably 90% of people walk right out of that park and right into Disneyland, probably increasing that park's capacity visitorship(?) by 50% for a few hours, clogging pathways and rides. Remember that Disneyland is 85 acres and DCA is 60 (whereas Kings Island and Cedar Point are around 360). The idea being, people treat it like one giant theme park, so people with the $190 Southern California pass who come after work really bottleneck the place by traveling back and forth between the parks. When Cars Land opens in June, that ease of travel will backfire, as people flock to World of Color, then return to Disneyland for Fantasmic, then go back to DCA for Cars Land, etc.

If only the park's CAPACITY increased for those hours. It does not, and therein lies the problem.