We should probably have told poor PBO that one of the defining characteristics of the wonderful world of the theremin is that nobody agrees with anybody, and everybody is RIGHT.
Thierry, the question here was about "bonding" with the instrument from a "mental/psychological, ideas/rituals" point of view. This was not what we might think of as a scholarly question. It was more of a psycho-emotional question, and it seemed appropriate to give a psycho-emotional answer, rather than some absurdly haughty advice about the importance of first studying the violin and "refreshing" one's knowledge of music theory and history!
I looked at PBO's picture (zany and cute) and offered an answer I thought fit the question and the questioner.
As for painting and decorating the cabinet of an Etherwave theremin, Bob Moog himself thought it was very important, and made it a major part of his personal Etherwave-building workshops (I attended one of these back in 1997 in Portland, Maine). It is not true that people do not customize violins, cellos, pianos, and other so-called "traditional" instruments. Many highly successful, professional musicians have done exactly that! Since the Etherwave theremin has no tradition, and it's cabinet has all the flair and panache of a shoebox, I see no reason why someone should refrain from using their imagination in putting their own stamp on it.
I do not see this as treating the theremin, or its inventor, with disrespect. On the contrary, it often seems to be quite the opposite - an act of love of the instrument. One of my RCA theremins was once the property of Julius Goldberg, personal assistant and business partner of Lev Termen, and he customized his instrument by removing the conventional antennas and replacing them with wildly Art Deco "lightning bolts"! Was this "complete idiocy"? I don't think so.
I think it was wonderful!
PBO, YOU GO FOR IT! And as the Wizard said to Dorothy, "Pay no attention to the little man behind the screen". LOL