WARNING! Children should not use the handline. Never allow the handline to get wrapped around any part of your body. If entangled, there is a risk that significant pull on the handline can cause injuries due to constriction and could result in pulling you overboard causing death due to immersion in cold water conditions or drowning. Likewise, for very small craft (e.g. kayaks) if the handline is attached to your small craft there is a risk of overturning the craft which could result in death due to immersion in cold water conditions or drowning.
These risk are mitigated by selecting your leader strength such that it will break before the forces become strong enough to cause injury, pull you overboard, or overturn your small craft. Always keep a knife on you to cut yourself loose should you get entangled. Also, fish caught on handlines are usually very lively when brought on board. Use extra caution to avoid hooks, spines, and teeth.