I have a shorter but wide at the back leather strap on Pentax lugs for my 67s. I leave it on for no other reason than walking about taking shots when I am taking shots, and just handling the camera. I leave it draped on my forearm when shooting/handing ---- The 67 is heavy, it'll slip someday. I've only shot 67 for about 4 or 5 years and the strap has prevented at least 2 falls onto rocks and pavement, caught by the strap around my forearm.
Whether or not you carry a camera in the open in a dense population area isn't directly reciprocal to whether you own and use a strap. (Though I can't imagine there are more than a few out there that choose 67 for walkabout travel in Rio or Jakarta.
)
When I place the 67 on tripod I drape/loop the open end of the strap around the base of the center-column so that it isn't just dangling. Never been a problem. YMMW.