You definitely risk a clash between a well-tempered instrument (like a piano) and a violin, given the piano is just one big compromise whereas the violin can hit the theoretically correct note. Either the violin (typically subconsciously) tweaks the tuning of a given note to match the piano, or the note is too short to notice (given the main way to notice the difference is by spotting pulses, or “beats”, which is the phase difference between the two notes - which could be measured in seconds if it’s <1Hz difference).
Khachaturian loved playing with enharmonics - the violin concerto has runs where you get D# and Eb (or similar) in different parts of the same run - or worse, two different Bb’s, as the run implicitly moves through different keys as it goes. This is then made particularly fun in the lead-up to the cadenza, where the violin duels with the clarinet, and to sound correct, you have to explicitly coordinate on which key the various phrases are actually playing in (given it effectively switches implicit key faster than the explicit key signature). From memory, you end up with the clarinet deliberately playing very different enharmonics to the violin, giving it an incredibly otherworldly feeling.
edit: to clarify, you literally have to say: “so play this Bb as the Bb in a G-minor scale, and this Bb as the Bb in a Ab-major scale” or similar - as they have different frequencies. Or more accurately “play this subphrase as if it’s in G-minor, and this phrase as if it’s in Ab-major”. Despite the Clarinet having fixed stops, you still “lip” the notes up and down to get the right frequency.
Khachaturian loved playing with enharmonics - the violin concerto has runs where you get D# and Eb (or similar) in different parts of the same run - or worse, two different Bb’s, as the run implicitly moves through different keys as it goes. This is then made particularly fun in the lead-up to the cadenza, where the violin duels with the clarinet, and to sound correct, you have to explicitly coordinate on which key the various phrases are actually playing in (given it effectively switches implicit key faster than the explicit key signature). From memory, you end up with the clarinet deliberately playing very different enharmonics to the violin, giving it an incredibly otherworldly feeling.
edit: to clarify, you literally have to say: “so play this Bb as the Bb in a G-minor scale, and this Bb as the Bb in a Ab-major scale” or similar - as they have different frequencies. Or more accurately “play this subphrase as if it’s in G-minor, and this phrase as if it’s in Ab-major”. Despite the Clarinet having fixed stops, you still “lip” the notes up and down to get the right frequency.