tunnel around network roadblocks in emergency situations

I was reading a blog post about Lenny being in a hurricane shelter. He mentioned this:

I’m in one of the local high schools that has been converted to a shelter… I have wifi here but the school server blocks Yahoo so I cannot email anyone

None of these are guaranteed to work but here are some approaches. Most require some preplanning:

• use a TOR browser to access your email; the network won’t be able to see what you are accessing, so they can’t block the email provider. Of course, they could block TOR altogether.
• if you have a server somewhere else, proxy the browser through an SSH tunnel.
• walk around and see if you can find an open (unpassworded) wifi access point to do your mail through.
• a backup cell data plan can be very cheap for such uses. I use H2Owireless as my backup SIM. It’s something like $8 for unlimited talk/text and 1GB of data.

I don’t encourage folks to circumvent restrictions at work or school, but an emergency is an emergency.