Registrars are required by ICANN to routinely remind customers to update their contact info. One can ultimately lose the domain if the whois info is bogus.
While this is true, many registrars allow you to keep your identity more-or-less confidential.
Take an example, omgomg.eu, currently registered by myself. A typical whois will not reveal any results and will instead direct you to EURid's website for more information. EURid will reveal my e-mail address and
my registrar's contact info as "Registrant technical contacts".
All in all, if I wanted to remain anonymous to average users, all I'd have to do is change my contact e-mail to something that doesn't contain my real name in the username.