By “EK”, do you mean “electric keyboard”? I’m just guessing.
Yes, by playing the piano first, a young child cannot play out of tune. However, they also don’t have to develop that fine ear to do it. Playing the violin is like a two-edged sword. On the one hand, the child who has a good teacher, a fine instrument, precise recordings to listen to, and parents who will help them practice, will develop a better ear than their musical peers who didn’t study violin. One of my vocal-major friends in college had a scholarship as a violinist in the orchestra, but had to drop it because of the time commitment of being in the college’s opera quartet. She had a superior ear, and our teachers always attributed it to her early violin training.
However, if the instrument a young student has won’t stay in tune, and more especially, if they don’t practice with the expectation that they always play in tune, they won’t develop that much-desired ear, and they would be better served on the piano, as SoftMozart suggests, because the mechanics are simpler, they learn to hear and create harmony, and basic piano skills are often required for professional musicians. Every music major in most colleges has to pass “Keyboard Harmony”.
I think that it is easier to learn to learn to play the piano vs the violin right, but if the parent is prepared to help the student practice and provide for the potential shortfalls of developing a fine ear on the violin, then the violin could be as beneficial as the piano. For some families, there isn’t space for a piano, and the portability of the violin makes it a better choice.
With my young children, I did buy them a small violin, but we have sunk into the routine of piano. We also do a lot of ear-training and singing exercises (aka games) with hand chimes and our orchestra-quality glockenspiel. This is helping them develop their ears like the violin would do, while also giving them the kinesthetic experience of playing an instrument. These instruments are very portable, and we have had a lot of fun experiences with them. We often do singing practice in the car. We always have our voices with us! If I had to drop piano or ear-training/singing, I would drop piano. However, I have no intention of doing so.