LensRental website has a quite interresting blog post about salty water damage and a A7sII:
Lens Rentals | Blog
What is interresting is that overall:
- salt water is much worse than std water as the salt corode things weeks and months after the fact
- most servicing will not accept to deal with a camera that got water inside as they can't offer a warranty on their job. A component that still work today may stop working soon after due to the water damage.
- Once you got water damage, most often a new camera is needed. You can't trust the old one anyway even if it is still somewhat working.
- No camera DSLR/mirrorless do offer water proof.
In the end, I managed to get non WR compact bodies in the past in the rain and all and that our WR camera and lens can still fail I am not sure if all this stuff is that great. None of my lenses are WR or AW, and I got away in many wet situations, taking some care of the gear but still. The key point is taking care.
Anyway one day it may happen even if you do your best. To me you shall always have good enough insurrance of good enough finance to be prepare to replace your gear. It may be water damage, it may be something different. It may be related to camera, but could as well be your car, your dishwasher or whatever... You need some a plan for when it occurs. You may never have issue with your camera, or your car, but it will happen to some of your properties.