Recently a consultant revealed to me and my superiors that a particular department in my company had a tremendous decline in productivity over the past year. This department happened to mostly work with laptops and tablets and thus had wireless. Our barracuda did not display any vast amounts of internet entertainment and so I was initially puzzled by his statement. However he explained that more and more employees are using "hotspots" that when not broadcasted, become invisible to our network. So basically these people could connect to hotspots and watch youtube all day and we would never know it. The consultant also said that this was becoming an issue for many companies. So my question is, how can I detect invisible hotspots? I was browsing google and there are several different programs that can scan for such access points. But I am hoping to get a recommendation from the serverfault community. Thank you.