Understanding the basis for a decision will help you decide whether a challenge is justified.
Legal requirement - it's specifically detailed in health and safety at work legislation
Health and safety law deals with risks created by a work activity or undertaking - whether a business activity, or the activities managed or delivered by organisations like local Councils. Sensible precautions are explained in HSE guidance, including for voluntary activities.
Other legislation designed to protect the public/consumers may require more specific precautions. If there is no work undertaking involved, health and safety at work law does not apply.
Internal policies or procedures
Health and safety at work legislation requires employers to do what is reasonably practicable to manage risks, and so employers need to decide what steps to take. Some organisations may put in place detailed rules and procedures that go beyond the requirements of the legislation. This may be for ease of implementation, or might possibly be due to over-zealous interpretation or being risk-averse.
External advice – instructions or advice have been given from another organisation
Risk management decisions are sometimes complex – and can involve balancing issues such as civil liabilities, human rights and costs of insuring activities. Understanding this helps put decisions in their wider risk management context. It's also important to identify whether the advice given is specific and relevant, or general advice that's simply not relevant to the actual activity.
A local manager - introduces a new instruction or decision
Sometimes managers need to make decisions on limited information, or following an incident. Separating proportionate decisions from knee-jerk or 'jobsworth' decisions is not always easy – when local decisions are made expect to see clear explanations about why the precautions are considered necessary and are sensible.