I think it's a great idea and we've been evaluating it.

However to make it happen our system needs to have 0 false positives and we are not here yet. If your system made a mistake and you just disabled the account, angry customer will appear on the chat support in 5 minutes and the problem is solved. On the other hand if you pretend to be sending, you can loose all the customer's emails and that'd be nightmare.

Well, if you have an accurate enough system, you can send the clear, five-sigma cases to this queue and ban the more borderline customers.

And this is obviously something you can't discuss, but I wonder if you guys "seed" various sites with false emails as "markers". It would be a very cheap way to detect indiscriminate scrapers and bulk spammers.

That's basically what Craigslist does when it "ghosts" content. It tells you it published it, and you can even see it when you follow the direct link, but it doesn't appare on the listings. Eventually CL spammers started checking the actual listings.

I assume the same thing would happen with email; spammers would use a few of their own email addresses on the list to make sure the emails are actually being delivered. It would be a pain for a while for sure.

HackerNews does the same when it hellbans people. Let's just say it works for some kind of spammers (the less professional ones).

Personally I think sending some email through at varying and random amounts per day (for example) would be more effective, the rationale being to reduce suspicion of being blocked.

The legal and ethical issues surrounding this strategy is something to consider, though.

Hellban for spammers! Only on HN :)

This is how you treat credit card fraudsters too. Those that use your site to run a bunch of stolen cards trying to find the active/good ones. You start telling them they're successful or false randomly in what looks like a normal process.

This seems like trouble if they're still paying for it though.