Do you know what he was spraying? It could be fert or trace elements..... or just water to wind up the nosey neighbours.
On my spray test ,examiner asked me to proceed to spray field as I normally would, I REFUSED because it was blowing an absolute gale, he seemed completely unconcerned , and said alright, tell me how you would do it. Never moved sprayer at all on entire test .It’s the same here.
They don’t seem to have any concept of ‘too windy’. Unreal.
Ah, big farmer, say no more, say no more... Bad farming practice indeed. Does he no-till as well ? I bet he does, he's a no tiller isn't he...