Must say that I prefer the groups approach with restricted build access for "probationary" players, and the default being no build access.
I think judging the whitelist approach as an effective long term solution/protection on the strength of a few days is fraught with danger. And that's from someone with a lot less work to be lost than many who have built some amazing structures.
Using Kazaar (nothing against him) as an example, he's what we would classify a "pubber", he popped on the server one night having found the IP via google or similar I believe. He built for an hour or two that night, registered on the TOG forum here and his only post has been to ask for whitelisting which occurred. Now IF he'd been intent on destruction that's not much of an investment to then the next time he logs on start burning down every wooden construction he finds and causing other untold destruction. It's not hard to warp around to a spot where the owner is currently not logged in and destroy stuff without anyone who is on the server knowing.
Just my 2 cents
EDIT: Ok going to other thread
. Was typing while Fate posted