Not every CPA or lawyer knows about SUT. In fact, most of them pretty much have heard about it, but that's it. The ones that have some expertise didn't learn it in school - they learned about it on the street. They either got assigned to it at a job or lived through a few audits. From there they started reading about it, going to seminars, etc.
Here are a few litmus tests to see if YOUR auditor knows more than you do about this topic:
1. Ask them what they think of Quill. This is one of the biggest court cases involving SUT. They should have heard of it.
2. Ask them what they think the chances are of the SSTP becoming a reality.
3. Ask them what SUT newsletters they regularly read.
4. Ask them what books and online resources they use to research SUT.
5. Are they also an expert in income taxes? Good SUT experts are almost always specialists to the exclusion of Federal Income Tax. Their primary practice should be sales and use taxes, or a little more generally, state taxes.
6. Ask about the drop ship laws in your state.
Sales Tax Guy