Who Is My Client?

It may sound simplistic, but you should always ask yourself: "Who is my client?"  Making it clear whom you represent (and conversely, whom you do not represent) is an important part of establishing a retainer, and also helps you manage conflicts.
Consider, for example, a prospective client comes to you to discuss a joint venture she is planning with a friend. That friend may believe that you will represent both parties. If you do not take steps to correct the misunderstanding, problems can arise. This is one of the reasons you perform the conflicts check at the beginning of the relationship and before confidential information has been imparted to you. In another example, you might be acting for a company and find yourself receiving instructions and information from a shareholder and from a director—if you haven't established who has capacity to instruct you regarding the company problems, a conflict scenario can easily arise.  Determine who your client is from the outset.
As a practice, it is prudent to send non-engagement letters to individuals who you will not represent.  You may also advise them that you do not want to be contaminated with their confidential information.
It is essential to document communications with clients that make the scope of your retainer clear. You do not want non-clients to act under the misapprehension that you are protecting their interests, and you do not want these individuals to provide you with confidential information. Whenever appropriate, provide a non-engagement letter to the prospective client or non-client.