I use the Sony Reader for security.
And I bet a lot of people do.
I feel a lot more secure if I have books with me even for short trips, and this can, frankly, metastasize...... so I put my Sony Reader in my purse, with its 62 books on it, and I am perfectly secure. For long trips, I also take the charger.
This doesn't help with the need for security knitting, mind you.