I've spent an inordinate amount of time banning fraudsters from my own cloud platform. The bots that companies write to do this are designed to fight off other bots. If you have an appeals process, the humans that control the malicious bots will show up to abuse the appeals process. One of my favorite cases was a user that signed up with hundreds of stolen credit card numbers (all from the same IP address, as they are apt to do), got banned, and then opened an issue in our open source repo complaining of trouble logging in. Yeah, you're having trouble because I banned you and your entire network of bots.

There is a balance, of course, but if you haven't seen how much automated abuse there is on the Internet, be careful of what you wish for. Even the tiniest of the tiny services suffer from massive amount of automated abuse. At that tiny scale, it was nearly impossible for me to keep up with the abuse without the help of automation, very broad bans, and deleting related accounts by walking a reputation graph (like Google is being criticized for doing here). At Google's scale, I don't think there are enough humans on Earth to deal with the abuse. As a result, there are going to be some innocent casualties.

I don't think it's an ethics thing, it's simply not possible to run a business without some sort of process like this. There are laws, rules, and processes that could cut all this down to levels that could be managed by humans, but the cure might be worse than the disease. (For example, it would be great if there was a 1:1 mapping between your national ID card and your IP address. All of these stolen-credit-card users could then be imprisoned. But, you know that that's a terrible thing, because it will also be used against anyone criticizing governments or large corporations.)