My guess would actually be that the person has Apple Sharing enabled. Just make sure you have "Personal Sharing" and "Printer Sharing" disabled in your Sharing Prefs.
In the old days Macs used Appletalk for their LAN traffic. Latterly they used a TCP/IP stack and Appletalk in parallel and now modern Macs have pretty much ditched Appletalk and use afp over TCP/IP. This is probably the "nasty network traffic" your sysadmins are referring to
In the old days Macs used Appletalk for their LAN traffic. Latterly they used a TCP/IP stack and Appletalk in parallel and now modern Macs have pretty much ditched Appletalk and use afp over TCP/IP. This is probably the "nasty network traffic" your sysadmins are referring to
