But still, you'd think they'd rather change the sign only twice rather than FOUR TIMES.
Possible that the OPEN sign is covered by a CLOSED sign at the end of the season, with the intention of leaving CLOSED up all summer, only some prankster made off with the CLOSED sign in the meantime. The private venture operating the road in the winter might basically go into hibernation in the summer, and not routinely check the winter road entrance about 70km northeast of Yellowknife. But so long as they resume their checks by the time the lake starts icing over (when the venture needs to start getting the road ready, anyway), and continue them until the lake liquifies again in the spring, no real problem besides giving people a chuckle.
Still, if they ever need to redo the entrance sign, I agree it would make sense to make CLOSED the default, and cover it with an OPEN overlay in-season, when the venture's security patrols are keeping an eye on the road and its entrance sign.