Truth is, ALL of us have had new customers with difficult circumstances. I believe if we back away simply because of difficulty, we are beguiling our calling as tax professionals. There are most likely some of us who fear the possible liability, and that is a business decision incumbent on each of us.
Having said that, there are some situations I won't engage. Potential customers who are obviously lying, customers who switch preparers because they haven't paid last year's bill, etc. But for difficulty? I won't back away if there is any way to make the client well going forward.
Our blonde colleague from Florida definitely has a train wreck. I agree with CBS, establish a balance sheet that will enable future compliance. And explain that it will require extra work, and don't go too deep without getting paid.