Elderly people are often anxious and uncertain in traffic.

Factors such as impaired vision, hearing or mobility often make it difficult and more stressful for elderly people to travel safely.

Using your horn to let handicapped people across the road is likely to be construed as harassment and is also prohibited according to the traffic rules.

Both children and cyclists are considered vulnerable road users, and it does not matter much that you were obeying the traffic rules if any of these road users are injured as a direct consequence of your actions.