Be aware and factor in, that some instructors may be having an off day. The object of group management is to keep the group together so that help is available if trouble arises. The minimum party size is 4. In the advent of an accident, two can go for help, while the other remains with the injured person. It also often takes at least two boats to assist a swimmer and recover loose gear.
Additional muscle is handy when a rescue is required.
If less than four people go on the river, it is not deemed a club trip. As a guide, add two hours to the expected trip time to allow for emergencies. To avoid misunderstandings on the river, formal briefings are to be given at the beginning of all beginner trips, trips where there are new paddlers to the group, new or difficult rivers, and flood conditions. In less formal situations, a briefing of some kind is required, as it may not be clear who is responsible for what. Indeed, some members may have completely different views on their roles.