Costume or bathrobe?

My friend put on a costume which he called "International Man of Leisure" before we went out for Halloween in West Hollywood. From the time when we were at dinner to the streets of West Hollywood, people kept saying, "Is it a costume?" Or is it just a bathrobe?

I guess my friend's concept is that he wants to dress up as someone who goes to the spa every day and doesn't have to work. Is it too high concept for people?

Halloween or Spa Night?