How do you explain SEVS, RAV and the 25-year rule?

A customer asked this week whether a Japanese-market RAV4 could come in because it was on SEVS, then someone else said the 25-year rule makes that irrelevant anyway. I know the exact model code and build month matter, but the overlap between SEVS, the RAV and the 25-year rule still seems to confuse people. How do you explain the difference without turning it into a lecture?