No, it's a bad thing, because Nintendo could be losing potential customers, if someone went to the store to get a GCN, but the store didn't have any GCNs left, then there is a chance that they could just buy a PS2 or Xbox instead, or just not buy anything but lose interest in GCN.
I know when people hear that "GameCube is sold out", it sounds like it's in high demand, but really, i don't think that is so effective anymore.
You need to get more damn GCNs in stores Nintendo. *shakes fist*