Five swimmers considered missing: Major sea search was mounted after they all forgot to check in after an open water charity event.

Does this illustrate how difficult it is to hold an open water race or what?

From The BBC News website:

Watch manager Maddy Davey said: "Obviously with nine swimmers missing, it was a matter of great concern

"We wouldn't deter people from raising the alarm, but lessons were learnt for organisers and participants to check-in at the end of the event. ..."

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