WiFi Access points are far more of an issue these days. For a trivial amount a manager can have the printer where he wants and not even have to call the IT people. Bang goes your security policy.
War walking is far easier and a lot harder to trace. With war dialing the phone company will have a record of the who made the call and then it is just a case of back tracking. True it may be many steps but there is probably some sort of trail.
Unless a network is running intrusion detection finding a new node on the network will be hard and if the person knows enough to hide what they are doing almost impossible.