Grass cutter killed by landing plane
 

This seems to have happened a couple of times recently this being the most recent sad incident.
Oklahoma woman riding lawn mower dies after plane wing strikes her (usatoday.com)

I expect a straight-in approach was used.

Per the flightaware link that is exactly what they did.

It would be interesting to see what the local rules says.
. We had a similar discussion years back in my small airfield after an aircraft did land while one of us was mowing the runway grass. In practice, frequency was not manned , we did not issue a NOTAM. and the guy mowing wears ears protections and looks at the grass. So only the eyeballs of the pilot on finals can save the day. But if the small mower color is green and the guy wears dark clothes the chances of spotting it on time is small... We learned from that.