Hi -
I had heard the exact same thing. And, I believe, it's up to the individual registrars to enforce the ICANN rule(s). So, as Namepopper suggests, I don't think there's any "standardized" answer ... it MAY be different from registrar to registrar. Also, minimum Admin. info (for instance e-mail, or e-mail and address, or e-mail and Org. name, or address and tel. number) doesn't appear to be standardized, either. I may be wrong, but this is the gist I've heard over time.
Finally, I do know from a friend that whatever you do, RESPOND to the Registrar if there's a question or inquiry. If you don't, or you have an old e-mail address (my friend's case), it can be forfeitted within a time-frame they so designate (which I'm sure varies, as well).
Man, I'm out of breath now ... sorry about that! Hope it helps a little.
-Meg

PS. Any experts??