Well, considering the wet conditions issue exists and persists on every Model S I've had (P85, P85, and my less than two weeks old P85D) as well as every other car I've ever owned, I'm going to have to call shenanigans on the whole thing with a TSB that replaces pads and such solves such a vehicle operation problem.
If there were a safety issue related to the braking system then this would certainly be a required recall, not some obscure TSB. Since no such recall exists it is pretty safe to say that no such mechanical safety issue exists. There is simply no combination of brake pads, rotors, splash guards, dirt protectors, etc that are immune to the problem of decreased performance from being wet/oily. Disc brakes are not enclosed as they need to be exposed for cooling purposes, and thus are subject to getting wet in wet conditions. This is pretty basic stuff that anyone who has been driving for any length of time should know.
In your example of after exiting a car wash, it is always good practice to thoroughly dry your brakes in this case even on warm and clear days. Water mixed with soaps and other cleaners, even after being rinsed, will linger in a disc brake system and cause severely hampered and unsafe braking performance.
Just "using" the brakes does not necessarily dry them. They need to be applied through multiple full wheel rotations, generally a dozen or more depending on conditions, to start to actually clear them of water and other friction-preventing agents. Regenerative braking lessens the load on the friction brakes even at low speeds, and so more revolutions are required for sure while using regen. In the cold this is even more crucial as ice can get into places and physically prevent the pads from engaging.
Again, all of this is for any car, not just Tesla. I don't see anything here that points to brakes not functioning properly outside of wet conditions anyway.
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I beg to differ. I drive a very predictable route to work and have done so in several brands of cars over the years. I get on to a freeway and drive for about 30 miles without having to use the brakes. My commute is against traffic and I can generally use Cruise the whole way. With the Model S I have to be very careful when I hit my exit ramp if it's wet because I've learned the brakes will NOT perform well until I stand on them for quite a few seconds. I never experienced this in other cars where I've driven the same route without touching the brakes for the same length of time.
I also have the same issue coming out of car washes. The first time I nearly drove straight into traffic at the car wash exit when the brakes were weak. Again, NEVER had anything like that with other cars.
The issue was surely present on the other vehicles, whether you noticed it or not. Keep in mind all of the variables here also.
Were your other vehicles automatic transmission ICE vehicles? If so, torque creep when starting and stopping requires use of the brakes, which would help begin a drying process when leaving a car wash, where in the Model S you aren't using the brakes except to hold the car at a stop.
For the off ramp situation, keep in mind there is regen at work here in the Model S also, and at highway off-ramp speeds is sucking up a large percentage of the energy needed to stop the vehicle that is then not needed to be dissipated by the friction brakes, requiring less use of them. In your ICE vehicle(s), nearly 100% of that stopping power is required of the brakes, so whether you realize it or not you are applying them more in the other vehicles (thus facilitating quicker drying) than you are in the Model S in this situation, and definitely applying them more in wet conditions than otherwise.
