Originally Posted by
TheOneTheOnly
If you're in an area that doesn't have good WiFi or cell coverage, you could also use an SD WORM card.
http://sandisk.com/business-solutions/sd-worm
Basically, once you write a file to it, it's impossible (in theory) for it to be deleted short of destroying the physical medium itself. It's certainly more expensive than standard flash media, and I'm not sure where to buy one yet, but no matter how many times the thugs impotently pressed "delete" once they've taken your device, they can't delete it.
They can take the card off you and throw it in the nearest trashcan, however.
[Edit: I write "can" in the strictly physical sense of being physically able to. Not going near whether they "may" do so.]