I think I’ve finally figured out all those times my MacBooks and PowerBooks refused to connect to coffee-shop WiFi. I’d thought maybe some low-level hardware incompatibility, or some difference in the way Apple and router manufacturers had implemented the 802.11 specs, or a strange electromagnetic field generated by my fillings… but no.
Those café networks just have a fear of intimacy. Maybe there was an “Is that all I am to you? A spam gateway?” conversation somewhere in their logs. For whatever reason, they had no interest in a long-term relationship — and certainly not long enough to give an IP address to every random laptop that swung by with DHCP on its mind.