Look up the information for your registrar. I own 20 domains with GoDaddy.com, and in their FAQ (
http://help.godaddy.com/article.php?...19&topic_id=&& ) , they specifically state that domains registered through them must contain valid data, or face termination.
Personally I wouldn't register with a registrar that didn't.
If you must, registrars will usually sell a privacy service that will curtail the casual stalker. Mind you most law abiding companies and countries will comply with law enforcement if need be to release the real contact information for the domain in question.