This won't work for a simple reason: No violin sounds the same as
itself from one day to another.
Violins are made of wood. Wood is acutely sensitive to temperature and humidity. Moreover, a stringed instrument made of wood is also sensitive to time: The strings stretch, thanks to the well-known phenomenon of "creep". They move around on the bridge as the rest of the instrument expands and contracts. They also stretch and shift with use. Violins use friction-fit wooden tuning pegs, so they certainly won't stay in tune over time.
Then, even if you place the instrument in a temperature and humidity-controlled environment, as soon as you take it out of the case and play the thing all bets are off. A violinist is a big, moist, warm thing, in intimate contact with the instrument, who keeps moving the strings back and forth and up and down while applying strain to the neck.
Nobody who actually plays an instrument like a violin [1] would doubt that a violin that sits in a box for six months will sound different than it did on the day it was put into the box. The only question is whether the difference is systematic or random, and whether there is really any "mystery" there. I would hypothesize that if you stored your violin under conditions which simulated (to a sufficient degree of accuracy) the temperature, humidity, and (perhaps) string-stretching cycles that occur when the violin is used, you would find that the "mysterious" "sleeping" phenomenon would become undetectable. But by that point you've gone to an awful lot of trouble just to rediscover the usual rule of thumb: To keep your instrument sounding like it would if it were regularly exposed to a violin player who sweats just like you do (and constantly retunes the instrument to compensate), just play the thing every day!
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[1] I play the banjo. It's even worse. It's very hard to get the darned thing into tune at all (the source of endless banjo jokes) and it goes out of tune very quickly. The pros spend a lot of time cursing airplanes (which tend to expose your instrument to a fairly profound temperature and humidity cycle, especially if you check it into the hold) and stage lights, which are nice and warm, and which therefore start putting your instrument out of tune the minute you go onstage. But even beyond that: The tone changes when you change the pick angle subtly, or put more or less pressure on the big drum head under the bridge, or put any strain on the neck, or stand differently relative to the wall...