Via iWantMyName’s FAQ on why they don’t offer a “domain privacy” service:
Here’s what you need to understand: Whether a domain name is considered “property” (like in .com) or just conveys “rights” (like .ca here in Canada), the domain is considered the property of, or the rights accrue to, whoever or whatever is listed in the Whois record.
If you use Whois privacy and some kind of dispute arises between you and your Registrar, and you were to go to ICANN or CIRA and assert your rights to that name, they would look at the Whois record details and tell you that you have no standing. The domain belongs to the “privacy entity” listed in the record.
In a trademark infringement case, a 2009 United States District Court ruling in U.S.A. held that, for domains with “private registration”, the privacy service is legally the “owner” of the domain. The privacy service acts as the “cyber-landlord of the Internet real estate”, and the domain is “licensed” to the customer of the privacy service.
Putting fake info in a whois record also causes legal-ownership issues (plus violations of terms). So the most responsible option is to put real information in and tolerate the spam and stalking.
It might be time to get a P.O. box and a Google Voice number.