In the bar shooting scene with Frau Hammersmach in the movie Inglorious Basterds, why were the basterds dressed as Nazis?

When meeting Bridget Hammersmach in the basement bar to discuss operation kino - Wicki, Stigglets and Hicoks were all dressed in Nazi military uniforms.This in itself attracted so much attention to them, and eventually put them in the dangerous altercation with the major. Why not dress casually and pretend to be Bridget's old friends? via /r/movies http://ift.tt/2v9bb15