When it hits the fan and all hell breaks loose, you need to have a reference to guide you through what needs to be done. Elements of a plan may include stabilizing the situation in the field, as well as taking the steps necessary to protect yourself after the fact in the event of threatened litigation. You need to know whom to call for various purposes, and how to deal with the news media to minimize adverse publicity. Finally - not only should an emergency response plan be prepared in advance, it should be tested so that you and your guides will be prepared to take to necessary steps and the plan will be more likely to achieve its objectives. This topic is discussed more extensively in AO's Risk Management Manual.
Common sense is ignored when on a trip with commercial clients.
All too often it is easy to get caught up in the clients' exuberance for the raft trip. The bottom line is the clients don't really know what they are getting into, and they rely on YOUR expertise to get them through the trip safely. Keep the trip within the limits of your clients - don't get talked into taking unrealistic risks. If equipment is forgotten or breaks, or if you are short a guide, don't stretch yourself, your guides or your equipment beyond prudent limits. If something goes wrong when you go out on the limb once too often, the optimism and exuberance of the day's adventure will disappear under the harsh light of hindsight.