Kalen,
I agree 150 feet is enough, and in that case, a "6 lbs of mansion got built on a 5 lb lot" at 170-180 yards off the tee on the slice side, about 135 feet off the CL. More than that, they saved a big tree front left of the tee, and have a creek left, and the wind typically blows left, meaning golfers had to aim right of the theoretical centerline, narrowing the deflection zone. Removing a tree would help, as the typical aim line for golfers figures in where shots go, no matter where the gca drew the theoretical centerline of play.
Back to the 150 feet, I delved through the available data, and at 170 yards or so, that captures from memory, 92% of "D players tee shots on the right side, left side 150 feet probably captures 98+%, 165 feet captures 100% of measured shots left)
On a 30,000 round course, a hair more than 16,000 balls end up right of the CL, and that means up to 1320 might leave the property......which might be 110-220 a month, depending on length of golf season. Of course, D players are the wildest, make up 16% of handicaps and probably a third of golfers, so on a course with normal participation across the spectrum, that reduces to 37-73 a month, which is still possibly 2-3 a day. All of this presuming no elevation change at the property line, no trees, no wind, golfers aiming at the center of the fw (within reason)
Not all would hit the exact same lot, which theoretically reduces potential ball strikes by 50-66%, and to less than twice per week for for any particular house. (Assume that 20 yard spread, or 210 feet, and imagine 70-90 foot wide lots along the course)
I am pretty sure the typical homeowner would measure the risk in terms of frequency, not % of shots, and consider once a week, month, quarter, or season to be a more reasonable measure of shots striking his house, even if there were a theoretical 92% safety factor.
I have run through the math at the 175 to 190 feet on slice side, and it greatly reduces the rates of foul balls in the stands, so to speak, up to 98-99%, which naturally reduces the number of potential ball strikes to once every 3-4 days, again, with no barriers. IMHO, trees which are famously 90% air but knock down 90% of shots, would reduce those to manageable numbers. So would any other ground level barrier. A 170 yard tee shot rolls the last 20 yards or so, which wouldn't be lethal or damaging, and the barriers could also come in a bit.
All of this is conceptual, of course. It would be impossible to apply to a given situation without further thought, though.