I think it works like with all other such jobs:
1. The rule is account expires after 180 days (or 6 months or whatever)
2. The cron task runs every so often and deletes expired accounts

Now, if the cron happens to run exactly on the 180th day after last account access, this is when it gets deleted. But more likely, these two dates do not coincide, so it might always take a few more days before the account is actually deleted. For example - if the cron runs every 2 weeks, it might take anywhere between 0-14 days after the 180 day period that the account gets deleted. What's more, the amount of extra days is more likely different each time, as you can imagine.

Anyways - 'account sniping' is such a very minor part of what a Go server is that I am surprised people even make an issue out of it. Man, I am surprised people actually do it. Just pick a nice name, and stick to it... The only reasonable reason for such 'sniping' i can see is when you let your own account expire by mistake and want it back... But then - people are weird...

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- Bantari
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WARNING: This post might contain Opinions!!

I suspect the housekeeping service runs nearly continuously, or at least several times a day. Click "File" and then "Sever Stats." Then, try it several minutes later. If there have been no registrations in those few minutes, you have a good chance of seeing that the Current number of Accounts dropped slightly.

The number under server stats includes guest accounts, which are deleted immediately upon logout if they aren't registered.

If you look at the game lists for the older aya bots, which play pretty much continuously, you can see that the earliest games are generally within a few minutes of 180 days old.

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Dave Sigaty
"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

Here is another question - what can be the reason if a game is "forfeited"? Can one always conclude "forfeit" -> "escaper who got punished"? I recently played "pomelo" and I noticed that whenever he left games he immediately lost due to "forfeit", but then I also saw an unfinished game in his list which shouldn't be there if my theory was correct.

You are only flagged as an "escaper" if you are the first to leave a timed, rated game. The unfinished games in his profile would most likely have been games that were either free, untimed, or he was not the first to leave.