Just to add to this topic the development of the story.
I contacted the Lexus of Cambridge again, and they have agreed for me to bring the vehicle in, so they can fix the rain sensor.
So I did, and they have fixed it.
Upon picking the vehicle up from them, two things made impression.
First, the vehicle was splashed with some white-ish water, so they can test the sensor, and they delivered it as it was, no washing it. Now many of you may say "Oh, what a big deal", but wen we are talking about "premium" cars and "premium" service, this is not it.
For comparing I will mention, that a Mercedes Benz dealer took my 1996 S420 for front end alignment and returned the car detailed, in and out.
Second, I have noticed the AC doesn't give equally cold blow between the driver and passenger side. I called the service manager, and showed him the difference. He acknowledged that indeed the AC was not blowing equally cold air from the right and left vents, and it was not blowing cold enough, so he advised me to keep driving it would get better. I asked him if the vehicle would be OK to take me to Croatia and back the next week, and he assured me I would have no issues.
During my 18 hour trip South I realized, the AC barely blowing cold. I was sweating and it was very exhausting driving like this.
I ended up finding local shop to refill the AC Gas for me, during which process we found out the AC unit has only 200 gram of gas in it, while it should have 600.
I was disappointed again, since I called it while the vehicle was with the dealer, and refilling (including testing the system for leaks) only took an hour and a half. They did nothing.
I am not sure what you guys think, but this, I can tell you, is NOT premium service. 🙂 Very mediocre performance.