Before a Player makes a bid that skips one or more levels, a Stop Card should be placed face up on the table to left-hand opponent, before making the (skip) bid. After allowing for any alert that may be required and any questions by left-hand opponent to be answered, the person who made the bid waits for approximately 10 seconds (but less at one’s own discretion) before removing the Stop Card and left-hand opponent may bid.
The sole purpose of a stop card is to remove from left-hand opponent any excuse for an unnecessarily long delay (i.e. possible unauthorised information) before making a call after a jump bid by the opposition.
While the stop card is out the LHO should use that time to make inquiries regarding the jump bid.
In effect, the stop card is an enforced pause – a discretionary 8-10 seconds. (In order not to give partner any unauthorised information, players are expected to pause before they bid whether they need to think or not.)
When a player has available to him unauthorised information from his partner, including from an unexpected alert or failure to alert, he must carefully avoid taking any advantage from that unauthorised information. When there is a possibility that unauthorised information has been conveyed (e.g. by gesture, comment, hesitation etc.), Law 16 applies.
You must refrain from bidding on borderline hands if the element of risk has been reduced by your partner's trance or hesitation.
You may take advantage of unauthorised information conveyed by your opponents but at your own risk. In the event of your being damaged by being misled by an opponent's inadvertent mannerism (e.g. hesitation with a singleton), you are not allowed to benefit from an adjusted result (although the opponents may have the score adjusted to their disadvantage).
Whenever you believe that there is a possibility that a Player may have been in receipt of unauthorised information from their partner’s gesture, comment, hesitation etc., you should immediately try to establish the facts about what occurred. This should be done as pleasantly as possible, stressing that it is just to establish the facts should the Director need to be called at the end of the hand. The Director should be called at this stage only if there is a dispute about what has occurred. If, at the end of the hand, the non-offending side believe that they have been disadvantaged, the Director can be called and there will be no dispute about the facts.
• If the Director judges that the outcome may have been influenced by unauthorised information, he/she may award an adjusted score as per Law 12C1(c), (D15).
• In making such adjustments, the Director must be satisfied that the non-offenders were damaged by their opponents’ use of unauthorised information rather than by selecting an inferior line of play from the logical alternatives suggested by all the information available to them.