When I set it up, I knew it could be annoying, which is why I automatically whitelisted everyone I knew. I was seriously concerned people would rather just not be able to send me emails and will willfully ignore my emails, but as I pointed out, that's the exception rather than the rule.

And I am proactive. If I see an email in the quarantine folder from someone I want to be on the whitelist, I press a button and he's in. This isn't a hard line, binary, black and white situation. I can and do place people in the whitelist.

If I've requested something from someone, I don't expect them to respond to the email, and I usually reply back to them with an apology about the email. So far, no one has complained.

And I don't use captchas. There's no need for them. All they have to do is click on the link and type in their email address.