Plentiful bandwidth, scarce chairs
Thread on Doc's site about how to meter access to coffeehouse seats. The scarce resource here isn't the bandwidth or the address space, it's tables and chairs. So what you have to realize about coffee places is that they aren't restricting access to net and power because they want to make money partnering with a wireless company, or because they want to save money on the electric bill. They just have to do something to keep the whole place from filling up with people who buy one cup of coffee and sit there working all day. One way is to treat the customer's laptop battery life as a parking meter for the chair, and another way is to charge for a net connection.
But if a place looks "dead", with no customers, people are less likely to come in. If you're running a coffee place, you want some but not all chairs occupied. So, in the grand tradition of obscure technical fixes to social problems, what about this: treat net connections like chairs by setting the DHCP server to give out a limited number of addresses, say, number of tables minus two. If the place is full, someone coming in can't get on until one of the current users leaves. Put up a sign: "The number of active Internet users is limited to 8. If there are already 8 people using the Internet, please wait for another user to leave before connecting."
That way you don't have to worry about booting out the people who tie up IP addresses and chairs during rush hour—customers will talk among themselves to figure out a fair allocation of the addresses.
This photo is the number one result for [chris dibona] on Google Image Search. (Yes, I'm doing a presentation for LinuxWorld Conference and Expo people and I want to give credit to the organizers of LINC, which became the first LWCE tech program.) Somebody reboot the Google.
Desktop anti-virus software is an example of something that IT people like, but that doesn't contribute to the bottom line. What happens when you deploy AV-free desktops?