No, there is a better way .
My local mechanic got fed up of people literally parking across his roller shutter doors, the only access to his business.
He put two big signs up, on either side saying words to the effect of :-
" Strictly no parking. Please be advised that vehicle vandalism occurs here. Smashed windows, dented panels, nails left under wheels on purpose, so park here at your own risk" etc.
Works a treat. The fear of something happening is usually more productive than it actually being done, as people can get angry if not warned and "something" happens, but they can only be remorseful if it happens AFTER they accept the "risk".