To tell you honestly, nothing will happen to your BP if you leave the water out for the weekend. If you're still very concerned, you can get a sturdier water bowl. Some people use dog bowls (which is probably the cheapest version).

Just to let you know, Ball Pythons get most of their moisture from their meal. That doesn't mean that they don't need water but your BP will be fine without the water bowl for a couple of days.