Team Balance is a gameplay feature that automatically balances teams that have been made uneven (for example, by a number of players disconnecting on one side) by switching one or more players at random from the side with the most players. When team balance is initiated, a timer appears informing the players how much time is left until the switch is made.
Though the balancing process is a necessary one, many players have voiced disapproval at being switched to the losing side shortly before the end of a match, or while playing on a team comprised of people with whom he is in charge of or engages in regular communication with. In such a situation, the switched player may choose to attempt to arrange a manual switch with a member of the opposing team.
It is generally frowned upon to switch back to your original team after being autobalanced (such as moving to spectate and allowing another person to be balanced, and reclaiming their spot on the original team).
In October 2014, Valve added the ability to call votes to enable or disable autobalance.
In December 2016, Valve released a new autobalance system and enabled it on all casual match servers. Should one team outnumber the other, a prompt will appear for select members of the larger team offering a chance to switch teams. Players switching teams are awarded more experience points at the end of the match. If no players switch, the members offered will be automatically switched. The members will still recieve experience points if they are switched automatically.
Since May 2018 Patch, the autobalancing system no longer request players to join the other team; instead, it picks a random player, giving them a notice, shortly before being switched. The bonus experience points are still given to the switched player, at the end of the match.