It came as no surprise to me in
Imaging Resource's weather resistance test that the Oly flagship did very well.
The test conducted is similar to an IPX-1 test; though water exposure is longer than 10 minutes (IPX-1). Most cameras, even without weather sealing, can withstand some degree of rain showers of about 1 minute or less. This should give enough time for anyone to cover the camera and lens away from prolonged rain exposure. The key factor in weatherproofing is time and angle of the ingress. How long can a camera withstand continuous water exposure under a specific water pressure and at what angle is the key to understand how well do the design of the seals hold up. Weatherproofing does not mean infinite water exposure, because even IPX67 is rated only for up to 30 minute of underwater usage.
The tests conducted are revealing, but not conclusive. The problem is that, it is a one off test and there are no repetition of samples involved in these tests. Meaning that, the Sony A7RIII may have weatherproofing, but poor assembly may have caused its unfortunate demise because Sony relies on tight fitting tolerances. And this is the problem we have today. There is little to no Quality Control in camera manufacturing. Basically we the consumers are doing the QC. We have seen instances where even some Olympus E-M1 and E-M5 had died from water exposure and yet some E-M1s can seem to survive even the harshest conditions. No one will really know if your particular E-M1 or E-M1 II can survive this type of water test UNLESS you do it to your camera. But then when the camera fails, who is paying the bill? And if you ask Olympus to cover the water damage under warranty, some subsidiaries will not cover it either.