Official betting is placing a bet on an event that will have a specific outcome and is paid out if the result of the bet is correct. It includes bets on a particular team to win, a certain amount of points or runs scored, the total score of a game (over/under), and other bets. Multiple bets that combine different outcomes are called parlays.
In baseball, it is illegal for any player to place a bet on any game in which they are scheduled to play or participate in. It is also illegal for a club or league official to place a bet. If a person is found to be engaging in such activity, they are subject to a number of disciplinary actions, including being banned from playing in the sport for life.
Betting lines are constantly changing, so a bet placed on a particular event at one time may have different odds or point spreads at another time. The money line is the current odds for a given event, unless the starting pitcher is changed, in which case the new odds will become the official line.
If a sportsbook has a mistake in a posted line, it will be corrected as soon as possible. Bettors who have made a bet on a wrongly lopsided line will have their wagers refunded. This is in keeping with standard industry practice. It is also in keeping with a desire to help safeguard the integrity of the game from match-fixing and betting-related corruption.