[fzeroracer]

Google tends to cache pages for a long time, banned users usually leave a long trail (and post on sites where they will not get banned) and deleted posts can be resolved by finding and asking the user in question. And usually people with regrets tend to be very, very loud in scenarios like this.

[MrPatan]

I skimmed the paper and couldn't find where they say they looked for those users and posts that you mention. Maybe I missed it, can you point me to where does it say they make an honest effort to find those people?

I wouldn't say that failing to at least try to look for the less-than-enthusiastic people makes this paper criminally dangerous pseudoscience, but it certainly gives me pause.