Let me add one more thing: for many people, if you can get the left shoulder strap to go over the keyboard (on a PA) it most likely means that strap is too long for the correct playing position. The right strap should always be longer and it will go over the keyboard (if you want) but the left strap normally is not long enough for that. (If you think your left strap is the right length and it does go over the keyboard it says something about your bmi, sorry about that.)
Of course, the most prudent players (I know one) always take off the straps before placing the accordion in its case, then put a cloth over the keyboard, and finally lay the straps on top (if the case does not have a special compartment to hold the straps or your music stand, as some older Hohner cases do).
Of course, the most prudent players (I know one) always take off the straps before placing the accordion in its case, then put a cloth over the keyboard, and finally lay the straps on top (if the case does not have a special compartment to hold the straps or your music stand, as some older Hohner cases do).