Also there is very little practically that prevents a registrar from putting in valid whois info (event their own info) and holding the domain on ice until the registrant shows up (if they want to for some reason that is). There is nominal carry cost vs. the aggravation of doing the wrong thing.
And there are cases where no whois info at all appears and ICANN is ok with that. There is a domain that I am trying to get now for someone that is at godaddy. The registrant (fearing a UDRP) told godaddy to delete the domain. Godaddy didn't do that they removed the name from whois so "no match" appears. Not kosher but they do that and ICANN doesn't seem to mind. They will wait 30 days and then sell it to us for $24 backorder fee. To me that makes more sense time wise then taking it up with ICANN (and I have high level contacts at that organization that I can tap but for $24 why bother?)
Back to the issue of invalid info. Typically the process would start with someone filing the complaint form with ICANN. Then we get notified by ICANN and get time to fix the problem. De facto, we can populate the whois with whatever we want and reply back to ICANN "problem fixed". ICANN will then reply back to the person who filed the complaint "problem fixed" (to simplify things). Can't vouch for what others may do, this is what we have seen happen.