Sitting with an idle laptop on a UW wireless network here at the Evans School, I typically see a constant 40-50kb/sec of traffic flowing into my machine. At first I thought it was somebody attempting to hack or DDOS my laptop, but digging into the network packets with LittleSnitch showed me that all of this traffic was due to mDNS (Bonjour) broadcast traffic from other Apple machines on the network.
This seems like a huge waste of bandwidth and battery life to allow these network broadcasts. Apparently other university IT administrators agree; Princeton University filters mDNS traffic from its wireless networks. It would be nice to see UWIT do the same.