You might try this.

Select a very quiet camera with a wide angle lens. One with a leaf shutter works great. Attach a neck strap to the camera. Set the hyperfocal distance on the lens. Note the minimum distance. Hang the camera around your neck. Attach an air bulb shutter release. Run the air hose behind the camera and under and through your clothing into a jacket or sweater pocket. Set the shutter. Stick your hands into your pockets. Casually walk around in public maintaining at least the noted minimum distance from any potential subjects. When you find something interesting, mentally compose the frame by turning your entire body. Then look away just before you squeeze the bulb. Casually exit the scene and rewind.

I've done this with both a Canonet QL17 G-III and a Yashica MAT-124G TLR. Both have leaf shutters. Never had a single confrontation as not a single subject was ever aware they had been photographed. Even up close.

A side benefit of the TLR is that almost every photo has the subject looking directly into the lens. Not because they suspected. Rather because they had never before seen a TLR and were staring at it. Nice.