And Jay’s way means it will be higher hinder than email validation — and that’s good.
As Jay said the most important meaning of validation is not fight against spam, but protect people that aren’t part of a forum.
And there is another point. When those unwanted mails starts come from a forum that forum is quite fast banned from everywhere, not that false user. So… it protects forum not to be another spam relay.
We have here a plugin that allow answering with email only and without registration. I would like to use it, but because it isn’t validating receiver I just can’t use it as an admin. Such system is so unlegal wide almost all sivilized world.