Around here, they have right-of-ways, for utilities. They run through the
adjoining properties, 5' on each side of the property line, this gives them
room to get equipment in, if needed.

Thats been my experience as well. The line will follow the street or
sidewalk, then maybe along a property line, then finally make a
bee-line for your house across your property. It would be odd to place
a sprinkler so close to a street or sidewalk, no? And if they did, I
think it would be the sprinkler installer's fault for putting lines on
a right of way.

So you probably have only your own sprinklers to worry about.

-Kevin