I could check the usernames on all accounts that make a post, but it's still not covering all cases.
My main problem is with the Trust data dump (which shows usernames, unlike the Merit data dump which shows userIDs), and this is the main reason I can't full automate it yet. I'll just leave it as is for now, with some manual fixes once every few weeks.
I don't say you should use last posts, instead latest log-in time (Last active on profile page) but as being said I don't think you will spend your time and somewhat potential damages on your computer to do this.
I meant you can narrow down the population of active users (with Last Active time, not with Last post) to scrap data.