I feel that these are feel good "solutions" that do not resolve anything. If the intent is spying on a company or organization such precautions would be greatly ineffective. For instance, even if you ban cameras the paid spy would probably bring something less suspicious such as a pen or button that contains a secret camera. Malware such as Stuxnet/DuQu/Flame (as well as many others) have proven to avoid detection for extended periods of time. Mind that these Malware have infected the actual work terminals themselves network-wide even through USB flash disks. Also mind that we only hear about espionage attempts that have failed to remain secret for one reason or another and perhaps many successful cases will forever remain a secret. One solution would be the elimination of computers entirely at a significant cost of productivity (and paper tends to be taken away from the office).

I'd echo the "NEVER trust and AC" post by SmallFurryCreature (593017). I'd further consider the scenario where a few computers or the entire network being compromised. Botnets have been around for a while and are a growing problem. It is possible for individual customers or even ISP owned machines to be infected by botnets that send out spam email in bulk quantities. You may not necessarily have the legal ability to monitor the traffic due to privacy laws. Perhaps you can setup a honeypot of your own or work with people that operate them to figure out which machines are sending out the spam. Does the ISP assign IPs in a dynamic manner? If so the problem may appear larger than it really is to an external viewer. Altering how much IPs change could maybe help as well.

Actually that alone could be a significant discovery because it would imply that the planet still has active tectonics which would in turn imply that there still is a hot core which in turn may imply the existence of an under ground thermal-based life similar to those observed in deep underwater volcanoes here on earth. Mind that Ammonia (a possible by-product of life) was discovered on Mars in 2004 which got people quite excited. Of course any of the steps could lead to different conclusions which is why NASA is not even implying what discovery they think have made. http://science.slashdot.org/story/04/07/15/1637207/ammonia-could-indicate-life-on-mars