Waterproof case for A570IS or Waterproof Camera

I need to get a waterproof camera for my daughter that's going on a
week-long canoe camping scout outing in the summer.

I thought about getting the Canon WPDC12 for her A570IS ($175) but then
I saw the Fujifilm FinePix Z33WP for $133 and the Olympus Stylus 550 WP
for $104.95. She isn't going to be doing underwater photography, but I
want her to have something that she's not so worried about getting wet
that she keeps it packed away in a waterproof bag the whole trip.

Even though the A570IS is a better camera than either of those two, I
just wonder how much of a hassle it is with those waterproof cases to do
things like change the batteries, then get the camera back inside and
make sure all the gaskets are properly seated and lubed.

Has anyone here used one of the Canon waterproof cases?

 

Thanks. Yeah, I'd have to get some extra batteries too as there will
likely be no places to charge batteries along the way. Have you done
Northern Tier?

 

dpreview did a review/comparison of several waterproof compact cameras
a few months ago. You'll find it here:
http://www.dpreview.com/reviews/Q209waterproofgroup/