Per Boysen wrote:
This is essential to prevent mechanic shock damage in case of hit impact. Basses and guitars may have a very high tension balancing string pressure and neck adjustment pressure. The wood is firm and doesn't take damage by a hit, if stuffed up well inside a good case, but the strings are loose and therefore take up the energy of a violent impact.
I can't see it making a lot of difference with a solid electric instrument. Except that the truss rod might cause the neck to resettle while the strings are loose ( not so good) Surely that advice is intended for acoustic instruments where delicate soundboxes are tensioned by the strings? Or is there evidence? At least there's less chance of the security check guy playing Stairway to Heaven on it. andy