I wonder how this became Jersey week (as in why did everyone choose that week to go), as well as how it became a crowded time to go. In my town, the kids only get 2 days off (4 if you count the weekend), so if you want to go for a longer trip you have to miss school. I figure that a small percentage of families wouldn't mind doing that, but that number would be minimal compared to the number who would go on a full week-long vacation, such as winter break (February) or Easter break (Spring). Since those latter two breaks are probably shared with other states, you would think that crowds would be much larger at those times, yet I have heard that Jersey week can be very crowded. Plus, it isn't like it is the only 4-day weekend on the school calendar.
I am a teacher, and I have seen very few families go to Disney during that week. Some, but definitely less than February and April breaks.