A good friend of mine had a problem with mini motos riding down the open plan gardens to the front of his house...he ties a 20lb fishing line across his garden at waist height.
The first chav to hit it also snapped it, leaving no evidence. He went out to pick up the young man and advised him that next time he rode across the gardens he would set his laser to "kill" not "stun".
Problem solved
Simon
Please refer to this post and the whole thread, we've been through it all.
I have a friend who can't walk properly because of people like your mate, it is not legal or acceptable.
Dave