After their technician examined the camera I was sent a few photographs of what he found. Not having taken one apart myself I'm not 100% certain exactly what we we're looking at but I've added my best guess comments.
My camera is in Hong Kong so I can't use it for photographs so I've grabbed some stock ones from Nikon's website to help us work out what we're looking at in the technician's photographs.
Here's an AW130 - front and back views. Things to note are:
Moving on to the technician's photographs....
You can see at least four areas where water has been and corrosion has occurred. Of potential interest is the rust patch around the screw at the top right as this area is right by the seal that runs around the edge of the camera body. Is this possibly where the water seeped in? (You can make out the red O-ring sitting in a channel around the edge).
In order to work out which part of the camera we're looking at here you really need to look at the next photograph before coming back to this one. In that photograph you can see the 'ridge' that must locate in the slot with the o-ring at the bottom of it that we can see above. So the two halves mate together. This is also supported by the alignment of the areas of corrosion where water droplets have been trapped.
As the next photograph is the rear of the body of the camera it would appear that what we're looking at here is the inside of the back of the camera. Behind this screen I think is the display panel. The controls on the rear panel are off the photo to the left.
This shows the body of the camera looking from the rear - the area that was in contact with the metal screen shown in the previous picture. Looking at the profile of the housing we can see that it must be the right way up as the bottom is flat. The top profile corresponds to the raised section above the optics, and to the top right we see the on/off power button and shutter release button.
Also, at the left hand end, you can just make out three slight bulges that correspond to the tops of the three buttons down that side of the camera. There is no sign the single large large knurled knob that's used to secure the battery compartment as that's at the other end.
So what we are looking at here is the opposite end of the camera to the battery compartment / SD card slot etc. The main circuit board appears to be free of corrosion which would not be the case had the water made its way past it. The water damage is confined to the end of the camera opposite to the cover.
There is no way this water damage is a result of operator error
The final photo supplied showed the corrosion present on two of the connectors to the main circuit board. Once again this damage is at the opposite end to the cover to the battery compartment and is probably the reason why the camera stopped working. (The other areas of corrosion are not on exposed electrical contacts.)