In reply to tlm:
''These voids together with the slippery surface of the rocks pose a significant risk, and it is for this reason that we will continue to warn members of the public not to venture onto the structure.
Should a child or any other individual become entrapped in the structure for whatever reason, then the risk would be significant due to the majority of the structure being affected by the tide.''
Thier reasoning seem's sound enough to me, but a sign at either end would have done I reckon, if they wanted to warn people about the tide and gaps which could trap somebody.