Automation on the Playing Field

I had to laugh today when we went for a lunchtime walk around the playing fields.  There was the pitch line marker in the middle of the goal mouth of one of the football pitches with no one around.  And then it moved!  Apparently automation has come to the football pitches of Walsall and the line marker proceeded to mark out the whole of the pitch faultlessly and with arrow straight lines that no human could replicate.

Just had to take a photograph of the machine as it neared the end of its task. It is still apparently being monitored by humans, although they prefer to do it from the comfort of their vans in the distance.

I wonder what happens when the paint runs out?