Call me devils advocate if you like, but here in the UK I've seen so many sets of cones that extend well over a kilometer either side of roadworks with no real hazard to be avoided within them. I can get a great view of these things as it takes us half an hour to get through the congestion that results from it.
Not to mention the sets of cones that simply haven't been removed - there's no hazard in the lane they're blocking off.
I've been sorely tempted too many times to do just what those guys did. That said, if you can't spot wet cement you can't be looking too clearly either!