'Auto unstuck' was introduced in Patch 1.1.1. It is thought that the 'auto unstuck' feature simply calls the Stuck() function, but this is unknown as Stuck() can only be called from secure code. This 'spell' is called 'Stuck', has a 10 second cast time and a 5 minute cooldown. in the bank) or their hearthstone is on cooldown, then the game will try to 'nudge' the player in a seemingly random direction (though more often than not it will be in the direction they are facing).
The 30 minute hearthstone cooldown is activated as usual. If the player is in a part of the game world which they are unable to walk out of ('stuck') then the facility will give them some aid. Auto unstuck is a facility which allows players to get out of otherwise irreconcilable situations.