In 1999 I went out with a charter in Port Shepstone...
Was guaranteed some fish but ended up swimming after the boat capsized...
From my side as a customer, it is your responsibility for my safety. I know accidents can happen and no one will put his R300k rig in danger.
You've got no control over nature, if you feel it can be safe, go out but warn the customer beforehand of bad conditions. If they still want to go and you feel its save, then go...