eph6..... An interesting thread, like Whopity states I doubt many freelance instructors have no contract. The problem with contracts is that it ties down each side. The main thing is you have evidence of a business relationship. For example agree terms by an informal e-mail, how much you will get paid, who will pay for medicals and renewals. That way if you have a bad payer, and I have been there, you put them on notice and you just go to the county court.
In relation to CRB checks, or DBS as they are now known in the UK. CRB or DBS relates to vulnerable people such children under 16 or children under 18 if in full time.education. Also people say with learning diificulties, etc. There was a move by the CAA a number of years ago for all instructors to be CRB checked, but I'm not sure what happened, as I took to approach that I would only teach people over eighteen. I should add that Esther Rantzen, the founder of Childline, stated that CRB/DBS has gone to far in the UK, hence I think the CAA dropped the CRB requirement, despite which the responsibility falls on the organisation.
Regarding liability, I mentioned on another thread that setting up as a limited company is an option, it costs £15, but might not protect you, your family, home or estate. A good piece of advice I got from a solicitor, was in respect of the cover. Worse case scenario is that you have an accident and it kills your student aged 30 who is a surgeon and has a young family. So the insurance claim would be 37 years (working life) at a salary of 120K, which is about 4,4 million. So if you have cover for 1 million, you will still loose your house.