This is by no means the final word, but I do know this about the nebulous "shared network" rule. My Game Operator shares our concerns and flat out told me that he/she only enforces the rules.
Fleet Contact includes trading and military ships, while two individuals are connected to the same network. They did mention that sharing an IP address is not an infraction. Now, i don't know if that means that they use IP addresses to determine network. I have an email out to UIowa ITS to see what the deal is on IP assignment and what IP multiple computers on a router would broadcast. If they return and tell me it assigns different IP's I think we are in the clear.
There is a possible way around this as well. I noticed that the default gateways are different for the LAN, WPA2, and WEP access methods. This might mean that to get around the problem three people could each use one of the methods and trade simultaneously.
This is also a line I am pursuing with ITS.
As I had suspected, the University assigns distinct IP addresses. We can verify this using http://whatismyip.com/. This, however, may also not be the end of the story. However, in a stroke if genius, i tested both my home computer and allison's home computer running off our shitty little pedestrian netgear router. Both of our computers broadcast the same IP. My guess is that we are all perfectly safe trading amongst each other while in Schaeffer. However, be careful if you share a router at home and trade while on the same router.
I am again awaiting confirmation on this from both Ikariam and UIowa ITS.