In every game of Gin Rummy there must be a scorekeeper. This person is usually mutually decided upon by both players if there is a singles game and by all 4 people if it is a partnership game. In the case of 6 players, only 4 of those players need to decide who the scorekeeper is going to be, although it is always best to have everyone agree.
There are very distinct advantages and disadvantages to being a scorekeeper. The primary advantage is that the scorekeeper has the complete counts and scores in front of him at all times. This means that you can keep a look on how far ahead or behind you are at any given time and you will always be fully aware of what you or your opponent needs to win the game. The main disadvantage is that if you are playing in a partnership game, you have to stop as soon as any hand is over to write your own score, or the score of your opponent. Add to this the fact that while in the middle of your own play, you can be asked by any other player at the table for the counts on the score sheet. This can be a major interruption when you are in the middle of play, and therefore very distracting, especially when you are in the middle of an important play.
There is a very established and firm rule that the scorekeeper, while performing the function, is supposed to be completely neutral and not in any way working for his own side. That means that there is of course to be no cheating. The scorekeeper is also not responsible for any counts or any other information pertaining to the score, including that of his partner. The scorekeeper is also not responsible for any errors in the score made by other players in regard to their counts. When writing down the score, he or she should get a firm answer as to what their count is. The scorekeeper is not allowed to tell the person whether they miscounted, nor is he allowed to help count up melds or layoffs. It is up to the responsibility of each individual player when he is concerned about a count to verify the correct posting of the score himself. That means that other players can look at what you wrote down at any point in time to make sure you put the correct score on the score sheet.
The scorekeeper holds a very important position in this game, and it is one that should be given in trust. If at any time the scorekeeper fails to do his job, he or she can be replaced by another person, but only if the scorekeeper continues to make mistakes on the scoring. If the scorekeeper does not make any mistakes then they should hold that position for the entire game, not just through the individual hands. It is best to change up the scorekeeper when each game is finished to give everyone a chance in fairness.