I work in a development/code enforcement department. We generally mail a notice, then we knock on the door if things don't improve for a courtesy check before issuing a citation.

We don't want to send someone to court because they didn't mow their lawn.

And if there's a reason they cant mow their lawn or it tuelrns out the house is unoccupied, we want to know about it so we can plan to have a crew take care of it for fire safety.