Real life experience:
Bought 2"+ thick Walnut boards in Jan 2007. Stacked them outside with 1" stickers and a cover on top of black plastic. Boards were 6" to 8" wide by 10' to 14' long. Boards were really wet (fresh cut)
Milled them out and made a table out of them in Aug/Sept 2008. Have no idea of the MC.
Table has shrunk approx 9/32" over a 40" width after moving into an air conditioned environment. No problem thanks to breadboard ends and Behlens Table Top Finish.
No bugs (good wood: Thanks Jeff), no problems, but I would guess by the shrinkage that it still was not near 8%.
My conclusions: You ain't gonna get to recommended MC air drying here, but it still works good if you design for wood movement.
JMTCW
Go
PS: If you remember, we were in a "drought" most of that time. However, I am not going to say my storage was the best environment.