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.
Also, keep in mind when I wrote it, I was getting 20-50 spam a day (not counting unsubscribe emails). And part of the motivation was that legitimate emails were simply getting lost (I wouldn't notice them in the sea of noise). Checking once a week would mean scanning hundreds of emails for the few legitimate ones. The challenge-response is more reliable.
(Today I get almost no spam - someone fixed a broken pipe on the Internet).
My thought is that if i asked you for an email, and I was running a system like this, i wouldn't be a dick and make you jump through that hoop. I'd proactively add your email to the whitelist before you even sent me something.
Even if they have my address, how soon is it whitelisted? Like, they run home and update their whitelist?
In at least one case, I suspect this set up is narcissistic. ‘People have to kow-tow to communicate with me.’
You shouldn't bother writing unsolicited emails with your advice to people who may not care. It's a waste of your valuable time.