@Bombcar is correct. Once they've been legally notified of the potential issue, they have increased exposure to civil liability. Their lawyers and insurance com

@Bombcar is correct. Once they've been legally notified of the potential issue, they have increased exposure to civil liability. Their lawyers and insurance company will strongly encourage them to just fix it (assuming it's not a huge cost to trim back the stupid hedge). A registered letter can create enough impetus to overcome organizational inertia. I've seen it happen.