Usually, my M6 is hung around my neck and the Summilux 35 pre-asph doesn't protrude from my half-open ScottEvest The Tele-elmarit 90 and couple of TriX go in side pockets.
The SEV is useful in that I can also put, if necessary (rain, uncertain area) the camera in another pocket and it won't bulge (that's what the vest is designed for).
In summer, camera hung around neck on light grey shirt, so it won't show too much (My M6 has a black dot). Tele-elmarit goes on my belt in a black nylon case initially designed for a D-lux2, and the spare films in my jean.
It allows me not to stand out and yet have the camera at the ready. It usually works.
I wouldn't do that with my Pentax 6x7 though. 😀