Aside from the random piece of wood that will never grow up and behave, I think the builders will choose smartly from what's available. Companies that build thousands will certainly be careful vis-à-vis warranty costs and bad press, and individual builders even more so as they don't have volume and accessory sales as a pad against when 'good basses go bad'.
Personally, while I know that harder woods for fingerboards tend to boost a little high-end zing or even add a bit of shrillness in a few cases, I prefer them as 'extra insurance' when it comes to truss rod issues and setup.
Personally, while I know that harder woods for fingerboards tend to boost a little high-end zing or even add a bit of shrillness in a few cases, I prefer them as 'extra insurance' when it comes to truss rod issues and setup.