Are you kidding? I often register a new email address in order to register for this or that while still avoiding spam in the future. It takes about a minute to set up a new account at hotmail, etc.
It seems unlikely to me that the almost negligible effect this would have on vandals would be greatly outweighed by the number of simple typo fixes, etc., that most people probably couldn't be bothered to create an account to perform. I would argue that any time saved fighting vandals would be less than the man hours lost from anon editors who would just throw up their hands at having to register in order to insert a missing comma.
DickClarkMises
Date: Wed, 11 Apr 2007 14:53:08 +0000
From: Oleg Alexandrov mathbot@hemlock.knams.wikimedia.org Subject: Re: [WikiEN-l] Proposal to not allow editing without account To: English Wikipedia wikien-l@lists.wikimedia.org Message-ID: 20070411145308.GA6926@hemlock.knams.wikimedia.org Content-Type: text/plain; charset=us-ascii
On Wed, Apr 11, 2007 at 07:14:51PM +1000, Steve Bennett wrote:
How does us having a valid email address on record help the project? If the registration process is quick and easy, how does it discourage vandals? What problem will your proposal fix, and how will it fix it? It sounds like "vandalism is bad, so let's annoy new users".
That's the whole point I think. If you supply your email address when you make your account you're less likely to vandalize. And if you get blocked you can't start a new account with the same address while the block is on.
In short, people who want to be on the project will bother registering with a valid email, people who want to just vandalize won't.