at one street i lived in i had a idiot park in my space that i had bein using for over half a year, well i just used my car to push them forward a few feet (was 6am and just finished a long shift), left for work next evening to see a note saying if i moved their car again i would have "problems", so promptly knocked on their door and asked what the problems whould be, que sheepish looks from the BF who wrote it, and explained i hade a cam trained on that spot. never had a parking problem in that street again.