If this is still a concern (and I am on the same page.) There seems to be to ways to force the Tax-exempt Optional Statement in 2019 Lacerte. 

Settings > Options or Master Options > Tax Return > Tax-exempt Interest optional Statement

Or in the client detail 11. Interest Income there is a General Information link at the top of the 1099-INT tab which if you click opens additional input to force 

If this is not at all what you're looking for my apologies.