Musical Instrument or Deadly Weapon?

There are two musical instruments used in wind bands that can also double as weapons of war. One is  the piccolo and the other is the E-flat clarinet as shown here. It was the favored soprano woodwind instrument of the early military bands. A talented clarionetist can easily trim, comb, and part hair with the penetrating squeal of the E-flat while a less skilled player might slice off an ear.

From a postcard photo without markings, this young musician is identified only by the KB embroidered on his collar. So he is a member of the "K" City band which could be in almost any state in the US.

Note his high top shoes and his pince-nez glasses which were also worn by Presidents Theodore Roosevelt (1901-1909) and Woodrow Wilson (1913-1921). Therefore based on the fashion for those spectacles, I would date him from 1906 to 1915. But why did photographers of this era use a fur rug in so many studio portraits?