Neighbour being Petty?

[Andrea18]

My OH was cutting the front lawn and our neighbour came out of his front door and stormed over to my husband and told him that he would better clean up any grass clippings that went onto the earth of the border between our lawns.

Guess what? after the winds last night his border was filled by leaves and it looks a lot worse than a few grass clippings in the border.

They get trapped because the border is lower than the lawn.
Is the neighbour being petty wanting the grass clippings removed when in a few days they will have rotted down anyway and not been seen?

Well yes perhaps he is. However grass does not rot down in a few days. Talking from experience where I've brushed grass clippings into my flower beds and they been there for weeks.

Depends on how much grass is being left there

Stick up a low picket type border. Ignore neighbour.

How would he remove them?

I just dig the soil over, they will compost down nicely

Depends on how much grass is being left there

We are talking about what is left after the hover mower blows it out, it cannot be seen unless you look directly into the border

https://ibb.co/Jyc7vmc

Yeah, neighbour is batshit. I would propose a small fence as PP said and see that neighbour says. Or lay something across it to keep the peace.