Unexpected disconnections can happen for a variety of reasons. A laptop may run out of battery power, a wi-fi connection may cut out, or simply a power cut. Disconnections are inconvenient at best but if it happens in the middle of a hand where there is a significant amount of action then it can be very expensive. In general, if a player disconnects during a hand and cannot recover they cannot make any positive action in the hand and will fold when facing any bet. Their hand will not be automatically folded if they are not facing action and will participate in a showdown if their hand is still in play at the end. They will however be sitting out further hands until they are reconnected.
To reduce the impact of disconnections, players are given an amount of time to reconnect depending on the size of the pot. There is no disconnection protection offered whereby a player who disconnects will be considered all-in for the rest of the hand and can see the hand to showdown without having to call any additional bets. Internet connections are much more reliable than in the past, and this system is open to deliberate misuse.
In a tournament, there is no additional reconnection time allowance and a player who has disconnected and is facing a bet will have their hand immediately folded and will be sitting out (and blinding out) until they reconnect.
Sit and Gos
If a player is involuntarily disconnected, if they do not reconnect and log in within a period of approximately 10 seconds, they are removed from all SnGs that have yet to start. SnGs are short term tournaments. Regular tournaments do not have this policy.