Bingo games are games of chance and luck based on randomness. In the brick and mortar version, the randomness comes from the balls in the online bingo game machine being equally weighted so that all balls have the same chance of being sucked into the air tube and called by the bingo caller. These means that every number has the same chance of being called because there are no lighter balls that will be drawn into the air tube resulting in the corresponding numbers being called more often. If the balls were unequally weighted then the players would learn which numbers appeared more frequently and would select cards that contained these numbers in the winning positions and those cards would have a greater opportunity of winning than would other cards.

The game would no longer be a fair free casino game and each card would not have the same chance of winning and it would now be worthwhile for players to select their own cards. The equal weight of the free bingo balls results in the game being a fair game with each call representing an independent random event. This ball selection process is simulated in the software environment by a program routine called a random number generator, sometimes seen abbreviated as RNG. This program routine simulates the randomness of the ball selection process by use of an algorithm that results in numbers being selected that have the characteristics of randomness. This is why both online and land-based bingos are fair games.