I try to use contractors with whom I have an existing relationship, knowing that if they were to impinge upon my business with a client, it could jeopardize our relationship.
I sometimes use a “non-disclosure” statement in a contract, along the lines of:
This project is proprietary and must not be discussed while in-development, etc.
I also ask for a conflict of interest declaration, something that is standard in medical education – to see if a contractor does work for a competitor or a sponsor. It is ok if they do, but everything needs to be on the table.
Here is an example. I use a particular animation house to do 3D when it is requested by the client. Knowing who my client is, the animation house could certainly hit up my client for work, if they so chose to do so. However out of respect, they do not. By the same token, if a client asks me for a 3D animation vendor, I will give them the name of my own preferred vendors, who are honorable people to work with, and who do great work.
Speaking of lawyers, although unrelated, we have had a few shoots canceled at the last minute because the patient’s brother, who is a lawyer, started asking about royalties and scale pay.
Mike