A reader recently asked me about carrying your most valuable data with you on the SERE kit.
That is a good question.
I do carry a micro USB drive with me in my urban kit. In it I have not only data that might be useful in case of an emergency (encryted), but also I carry a tiny Linux installation that would allow me to boot any computer, connect to the internet (if access is available) and send a distress signal via email, SMS text message and several other less traditional methods. This is purely a last resort Linux installation that I created for this purpose only. I could use it to browse the internet using Tor but that's not the purpose of this.
It would be a good idea maybe to carry a full Linux distro in your kit for those times you are in trouble and need to gather intel online without leaving a trace. Maybe using TAIL Linux or any other portable distribution.