Yesterday I unsubscribed from the Knockout game, since I'm on holiday and thought I might not have time to play. When I'd finished, it definitely said I was unsubscribed, and to 'click here' to subscribe again. However today I've just seen an e-mail reminding to play my Knockout game. Did I do something wrong? Or didn't the 'unsubscribe' work properly?

Exact same thing has happened with me. I unsubscribed yesterday (Monday) and still got an email notification reminding me to play today (Tuesday Aug 3). Is there some kind of time limit we missed?

Knockout subscribers are copied into the "Registered for the upcoming tournament" register when the previous game resets. So, that is before Monday. If you're going to cancel your subscription, it needs to be done before the previous week ends.

I'll add a note to the game page explaining this, as this question has popped up sporadically over the past few years.