I think most artists would appreciate another musician wanting to ‘sit in’ with them and would happily accept a small correction in pitch. Music always sounds better when all the instruments are in tune. The correction involved amounts to a few cents. A cent is an interval equal to one hundredth of a semitone. A semitone it the interval between any two adjacent notes in the equal-tempered scale. Numerically, the twelfth root of two.
Amir, just because you, the great, trained listener, can’t hear small differences in pitch, don't assume no one else can. Let me tell you about a real trained listener.
Many years ago, I was living in Berkeley, CA making harpsichords. It was around Christmas time when I got a call from KQED, the PBS station in San Francisco. They needed a harpsichord for a concert they were going to broadcast and could I help them out. (KQED got my name from KPFA, the Pacifica radio station in Berkeley, for whom I had recently made a harpsichord.) “When is the concert?” I asked. “Tonight.” was the reply.
I didn’t have an instrument in the shop so I disassembled my wife’s harpsichord and loaded it in the back of my VW Microbus and drove to the city. There was not sufficient time to tune the instrument properly before airtime so I gave it a quickie with a strobe tuner. Moments later, the choral director came in to warm up his singers. He sat down at the harpsichord and played two chords. “Very nice.” he said. “You used an electronic tuner, didn’t you?”
Now, I can tell the difference between a proper tuning and a strobotune quickie, but it takes me more than two chords. Unlike piano tuning, for which an electronic tuner is sufficient, harpsichords are tuned to a variety of different temperaments depending on the repertoire and the desires of the performer. I wonder if you even know what a temperament is. I’m sure you couldn't hear the difference. You can’t even recognize the difference between a bass viol and a cello. (There is a thread where a YouTube video featuring a double bass is discussed and you comment that it is a great sounding cello.)
This is not my first unpleasant encounter with you, but it is my last. Adios.