I asked this elsewhere but seeing all these responses I would like your opinions here as wellDs is bring his SLR..he has the slingshot aw..so all good there. For those that have that bag--do you store your camera in it and take it on Splash or Kali? Those are the 2 rides he is concerned about..and man-who wants to trek ALL the way back to the lockers to stash it for that alone!
As I mentioned I use a different Lowepro AW. I am not personally knowledgeable about the slingshot. But for what it is worth my thoughts on this are....
A. If you are planning on hitting those rides repeatedly, I'd say leave it behind. If it's more of a one shot deal, go ahead and make sure you have it zipped up tight and make sure the raincover is fitting well AND will be in a position to protect the bag from the direction of water.
B. As soon as you get off the ride, open up the bag and check to see if moisture got in. It does happen and the bag isn't waterproof. But in my experience I've never had enough water to get in to be a concern. If there is any blot it with napkins or paper towels ( as I assume your clothes will be wet ) and hand hold the camera for a while with the bag zippers open as much as you can to let the moisture evaporate.
C. If you keep the camera and lenses in the bag while not at the parks it's a good idea to either leave the zippers open to let air circulate or to toss in a bag of desiccant if you can get your hands on it.
D. Even though it is the AW bag, it would never hurt to have a plastic shopping bag that can be stored away in one of the pockets that can be wrapped around the outside as an added layer... then disposed of after the ride. ( I don't normally suggest tossing the bag after one use because it isn't eco friendly, but if it's wet you aren't going to get it dry enough to fold up and put back in your bag for future use. Think of it as having already done double duty by your "recycling" it for use as a camera bag rain poncho. ) You could use the old trick of placing a strip of duct tape on cardboard the length of the bags open end and layering on 3 or 4 more strips which can then be pulled off when needed to seal the bags edge... it isn't waterproof where I would submerge it, but I've done this at the base of Niagara Falls in the spray and if it works there it will work on Kali River.
To sum up... yes I would take the camera with the bag on the ride.... but doubling up on the protection is never a bad idea.