No, but I have seen it.
Most of the time, we lay drip on top of the soil, under the mulch.
A lot of times, in new construction, the irrigation goes in after rough grade, then the sod crew comes in and does final grading and lays sod. Final grading can mean "we need 4" of dirt, just scrape it off of anywhere. " I have seen lines basically laid just below the sod, and acting like drip hose, becasue someone got a little too rambunctious with the skid steer.
Drip would be mostly wasted under 4 " for most plants I would think. Roots being up higher than that.
I wouldn't go much more than 14" on poly, or you will start having trouble with risers being tall enough to set your heads correctly.