This is close to what I have, except less complex. A single line in /etc/hosts that redirects sites to 127.0.0.1, which gets commented or uncommented. The fact

This is close to what I have, except less complex. A single line in /etc/hosts that redirects sites to 127.0.0.1, which gets commented or uncommented. The fact that I have to go through the hassle of sudoing up and removing the comment means I'm far more likely to catch myself before doing it and getting back to work.