You're filing SARs on structuring and the board thinks your customers would not structure if they knew it was a crime and that you would report it?
We live in a country where people are entitled to know what the law is. The best way to inform customers about the law is to make the
FinCEN Pamphlet available to them. That's the most effective, least dangerous customer training effort available. Hand it out when customers ask questions. Do an annual mailing to all cash intensive customers. Get it into their hands.
Going beyond that could morph into "assisting in structuring" at any time; e.g. you have 4 customers sitting around the table and one asks: "How does your bank know that I made deposits at two different branches on the same day or at the same branch two days apart?" I can think of a dozen more questions, but hopefully that one alone illustrates that you are opening Pandora's box. You said this meeting was to explain things. Now, you are refusing to explain things.
P.S. A different tack for your response to the board: A customer who is intentionally avoiding CTR filing requirements obviously does not need to be trained on CTR filing requirements - we have the best possible evidence that they already know what they are. So all the customer doesn't really understand is the SAR requirements. That's thin ice and there is no point in jumping up and down to see how thin it is.