Late betting

Late betting or past posting is making a bet after the time when no more bets are to be taken. It is considered cheating; information may have become available, including the outcome of the event, that was not available to those making earlier bets.

The term past posting originates from horse racing where a bugler sounds a "call to the post" just before the race begins. This is also the signal that no more bets can be taken. Any bets made after that time occur after or past "the post".

In other forms of gambling, the dealer may announce "No more bets" or wave their hand over the table in a specific manner. In roulette game for example, past posting refers to placing a bet after the ball lands in a pocket. The player has to distract the dealer's attention to be able either to move the bet to or to place a bet on the winning number. Past posters in roulette games play in teams. According to most cheating strategies the player who succeeded in placing a past posting bet and did not get caught is to make a few more bets (now legal) and leave the table.

This was more feasible in the days before live television or radio broadcasts of sporting events. It is featured especially in the 1973 film The Sting, which was set in 1936, as the basis for the successful con played on Doyle Lonnegan, played by Robert Shaw. In this case they used the wire transmissions of Western Union before they were made public to find results of already run races. In addition, Came a Hot Friday, set in 1949, and starring Peter Bland, showed a less elaborate practice of past posting, but in this case, the ruse all went wrong.

A variant of this is "pinching", where the bet is not moved but its amount is changed after the result. After a losing bet, the player removes chips from a stack through sleight-of-hand to reduce losses. The player may also plant high value chips underneath one or more low value chips visible on top, further reducing the payment for lost rounds, however, a bet found with high value chips underneath low value chips may be seen as suspicious. In either case, the top chip remains unchanged giving the same outward appearance of the bet, and will not be altered if the bet wins. This would be less practical to repeat over and over on the more long-shot bets like straight-up, whereas the even-payout bets on average would only require close to one pinched loss for every unpinched win.

...
Wikipedia