If I was having a bad day (which seems to happen often, touching his car would be scarey for me (liability, etc,) I'd probably walk my walker in front of his car painfully, get eye-contact with him and collapse in front of him and his car. (gracefully and making sure I didn't hurt myself. I am a good faller,knock wood.) Then it's his problem. Obviously I fear the legal system more than potenially embarrassing myself.