Paulp
Just to add my 2 cents worth. It's 24" to protect it from (amongst other things) the gardeners. Ref to "I saw all of that but my point is, is that this is a residence"... there is also some liability involved. What if you hire someone to work on the property, doesn't he have the right to assume there are no hazards (beyond the normal)?. If a worker cuts it and gets hurt there's a problem.
A short, true story. About 15 years back in the Northern VA area there wwas a 2 yr old who grabbed a hot wire in an apt closet. The last resident had bootlegged an outlet there and removed the outlet but not the wire. A painter painted the closet when the residents changed but told no one that he painted over an exposed wire. When all was said and done the court held the painter equally responsible (along with the past owner and the mgmnt) citing that a "reasonable man" would have reported the wire, even if he knew nothing about electricity. Seems to me that the same goes for knowingly placing a violation/hazard beneath the ground.
Just my 2 cents.