i don't know how many Q's one is required to pose to a customer prior to commencing work, in your field, in your location, so I cannot comment. I think no-one can comment for long about what will suffice in a court of law, as no matter what the precedents and the rules (of that jurisdiction you fall under) may be (and they may be clear or unclear), judges still have the right to pick and choose among elements and to draw their own conclusion.
In general, the more you can document the fact that "they" knew in advance something they didn't reveal, the more various lawyers involved will concede you have one good point on your side. Documenting is a way to reinforce a story. Video is good, letters written from one person to another are also not bad, if then he doesn't refute stongly enough what he may have already admitted. That's all I can say; more said is less helpful.
If you are not licensed and your friends are no longer "with you" as friends, you may scrape by this once but I would predict that from now on you'll need to write exams, pay fees, and treat every situation as a high-risk one from now on. A recent thread from an apprentice who was tempted to take work on the side dealt with this problem. It's because anything can spiral out of control at any time.