Right Lane Closed

Here is something that happens in Tulsa (maybe other places too) that is really aggravating to me. A lot of times (usually on the weekend) you'll see an orange, diamond-shaped sign on the side of the road somewhere that says "Right Lane Closed". So you'll immediately dart over in the left lane, only to find out that the right lane really isn't closed, and some lead-footed (possibly clairvoyant) jerk will pass you by on the right. Every time this happens, you'll see the cones or barrels that were used when the lane was closed on the curb. So basically the road crew finished up its work on the road and moved its cones out of the way. But these guys always leave the damn sign up. What's up with that? Laziness? Sick sense of humor? Incompetence? What?