Just an anecdote, but I once reported (by phone to the local gas company) a smelly local gas pipeline/junction that I noticed after cycling by on the road the next to it, so the leak could not have been all that small. I then reported it some weeks later because the smell was still just as strong (but still "faint" at the distance to the road).
Apparently no one cares about the little leaks everywhere (or they cannot be fixed cheaply). Later on I noticed that other gas pipeline junctions -- the type that are scattered around subdivisions -- often smelled faintly of gas. I wonder if these small leaks can be avoided with better engineering or if perfectly sealed pipe fittings in the outdoors are impractical.
