This is true. It's also especially annoying at Disney if you're staying in a room with only one bathroom.
While I hate being sick, the most annoying part for me was missing dinner at Ohana Thursday night and then our only day scheduled for the Studios, our last day.
This is exactly why buying a non expiring ticket is the way to go. If you miss a day you can always use it in the future.....there is no loss of money.