Snoozi says: "you snooze, you lose - at Card Hunter".

Who is Snoozi? Why You Shouldn’t Walk Away From Your Keyboard While Playing Card Hunter

We all know that your opponent going AFK in multiplayer can be very annoying. The chess timer prevents anyone from stringing out a game indefinitely, but 20 minutes of waiting can certainly be a chore.
If you have to go AFK in a multiplayer game, please let your opponent know and try to get back quickly. It’s not nice to make someone sit and wait.
Deliberate stalling in multiplayer is against the spirit of the game and the Terms of Service. We may ban players from further multiplayer on a temporary or permanent basis if they engage in this kind of behavior. To help us find players who deliberately stall, please report anyone who does so.
To report, just click on a player’s name in the score box in the top-left corner of the battle or on the post-game report screen or in the lobby. This should bring up a menu from which you can report that player. Please add a reason for your report.
Ultimate, we think reporting is the best way of dealing with this issue as you, the player, are the best judge of what is bad behavior and what is OK.
In the past, we’ve discussed other options for trying to eliminate or reduce stalling. One of these is options is a per-turn timer, which we’ve discussed extensively. Why haven’t we done this yet? The main reason is that Card Hunter is a turn-based game. Limiting each turn’s time is kind of against the spirit of the game, where you should be able to take time to think through a difficult situation. In addition, having a per-turn timer and a per-game timer is complex and tricky to explain to the player.

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That said, we may still implement a turn-timer if we feel that it is needed to manage this situation. However, in the meantime, we’ve added a halfway measure that stops players from just walking away from the game and leaving it – call it a wake-up or keep-alive message. Every two minutes, if you haven’t played a card the game will now prompt you to make sure that you are still present. You have 30 seconds to click this prompt away and remain in game. If you fail to do this, you will auto-forfeit the game.
Will this stop AFK behavior? No. However, hopefully it will reduce the incidence somewhat. We’ll still be relying on you to report bad behavior and we’ll continue to keep an eye on it. Let us know here how often you see this and how much of a problem it is for you.
Snoozi, the keep-alive gnome will start operating once we deploy the next build. In addition, we’ve added a flashing browser tab when a multiplayer battle starts if the game tab doesn’t have focus. Hopefully this will help with situations where you’ve tabbed away while waiting for the queue to place you in a battle.

http://www.cardhunter.com/2013/10/who-is-snoozi-why-you-shouldnt-walk-away-from-your-keyboard-while-playing-card-hunter/