Bailey wrote:
Maybe this potential stress issue is already factored in with the Payne drawings....
Kent it is IMHO. The Popsicle brace next in line below the neck block is a traditional method to deal with the stress riser created by gluing the fretboard extension to the top. The brace is shown on Michael's excellent plans.
Another thing that you can do that is yet another great idea from the House of Mario is to only glue the fretboard extension down with a small puddle of Elmers white glue, you know the old school glue that kids can eat and make, well you know....
The idea is that if the fretboard extension is not glued at the edges the stress riser is less of a stress riser.Others use A frame bracing and there are a number of other methods that I am aware of as well. Some folks make their living removing the Popsickle brace to "hot rod" the guitar and open up the top more.
As a guy who at times works in a busy college town repair shop we see plenty of guitars with the cracks beside the fretboard that you are describing. The Popsickle brace is no guarantee that it won't happen if the guitar is permitted to dry out or other stress occurs. But IMHO and that of other folks that I know it helps avoid the cracks.