With proper placement, gentle management, and selection of gentle lines of
 bees, 1-3 hives in a yard or garden pose no such problems as you list
above.

Right, there are a lot of variables. In fact, I had three hives on my land
all summer and no one but me got stung. But I spent a month thinking about
where to put them. I wanted 1) easy access, 2) plenty of sun, 3) a flight
path that would not cross the areas where the kids play.

My outyards have at least 16 hives and we are moving toward larger yards,
at least 24 hives. This many bees cannot be placed on a 2 or 3 acre lot
without creating a broad swath of foragers heading in the direction of the
flowers. Trouble is, which direction? Sometimes you can predict which way
they will go, often not.

I also have an apiary in the middle of a college campus. This has a tall
circle of trees around it so they fly straight up. Still, people have
gotten stung by them and I only keep them there because my department wants
them there. I would rather not have to worry about who might get stung
after I have taken off the honey or whatever.

I don't put bees in people's yards any more. In my youth I did, but I got
tired of having to go take off the supers in the middle of the flow and
move the hives out when I was already too busy. That yard I mentioned which
stung the neighbor, we moved it in July in the middle of a WILD lightning
storm -- but that's another story