I doubt we have 3000 newbies. And you just need to skim through the emails anyway, the purpose is to make it so that it takes 10mins to write the email but just 5 secs to skim through it. The guy creating 150 accounts would need to write 150 emails and send from 150 different addresses... impractical. We might still get the odd guy that uses his work email and his wife's email, but we are making it more difficult and at least we block the whales.
If we are going to start doing this, do we have an option for a refund? This is a complete absurdity from the simple fact that the sock puppets can and will send you emails with some dopey story. This is a time sink and detracts from getting a working coin out the door. My recollection is the social contract says funding accounts will be refunded so it isn't like NEM gains by keeping their money. And if NEM did keep their money, it'd be a black eye on NEM as a whole.
Closing registration? Now NEM is starting to really gain funds. If the devs are going to write a lot of code then they need the money, even if it does increase the chances someone walks off with the loot.
Last I knew you have to sit on this site and lurk for some time before you can even post.
In the end all you'll do is weed out the lesser intelligent "whales" or "scammers" or what have you. Also, you might want to consider that the people who go through the trouble to get a few shares might give more because of their increased stake. Having multi-accouters doesn't necessarily hurt the coin, it could in fact help.