Hi,
I just noticed that if you manually enter the date into the field with the datepicker plugin, it doesn't recognize it as an invalid year. This year we had leap year 02/29/2012 however if you enter 02/29/2011 it accepts the value. I'm not sure if this is a bug or a new feature but it would be very nice to have. If the date is submitted it could possibly cause a database error.
Thank you