Seems a fairly straightforward and simple suggestion.
We could build them today if it was truly economical (ie: if it wasn’t just cheaper/easier to hire South Americans with a pickup truck.) Given the more isolationist/militaristic stance of this setting’s United States it wouldn’t surprise me if the financial dynamic changed enough as robotics became more widespread. Wandering mowerbots would certainly explain the mysteriously open fields/short grass months afterward.
It would be amusing to lure row of zeds into one’s path at the very least. They could even occasionally chunk out a bale of twine, meaty mangles, compacted litter, or somesuch in their clippings making them useful as an autonimous resource gatherer.
Ideally I’ve always thought robots would be the proper place to start fiddling with multi-tile/component enemies (in a similar fashion as the current vehicle system.) However, at the very least they would probably drop some wheels/blades, an electric engine or two, bits of scrap, electronics and some solar cells.