Excellent post.
I'd just like to reiterate how important it is to have access to a good lawyer. Although most of your clients will be decent people, there will be one or two who turn out to be complete assholes. With experience you get better at spotting these people sooner and avoiding them. Alarm bells include: Being hard to reach, not returning your phone calls in a timely fashion, pleading poverty/extenuating circumstances, and asking you to start work at too short a notice. The parent also mentioned attempts to push a dodgy contract on you. These point to poor management skills, incompetence and general shadiness. Agreeing to work for them may be far more trouble that it is worth.
If they think you are just a lone freelancer, they may try to bully you into doing things that you do not agree with; that are detrimental to your livelihood and mental health. This may be "going the extra mile" and working extra hours for free to keep them happy. At worst, they may simply not want to pay you, thinking they can get away with it. This is when you need a lawyer to back you up. It sounds crazy I know, but there are people out there who will take your work and run away laughing,"So sue me!"
The parent's escrow suggestion is a good idea. You can also stipulate certain milestones in the contract at which you are paid a certain amount. A deposit up front is one way of testing the client's ability or pay. If there are sign of them having trouble, walk.