If swimmers decide not to compete at an open meet they have entered, then it is their (or their parents') responsibility to notify the meet organisers that they will not be swimming.
Withdrawal procedures are always laid out in the meet info, with either a phone number or email that can be used to let the host club know. This helps avoid empty lanes at Meets and means Competitor Stewards and Team Managers are not trying to locate a swimmer that has decided not to swim.
