Gait detection from shadows.
Big brother can sentence you to death in absentia then blast you to goo from orbit, but how will they find you? (See previous post)
Up till now you could leave the mobile phone at home, stay away from the internet, and wear a baseball cap.
Mornings and evenings will be the most dangerous, so watch out for strange men limping around on cloudy days or in the midday equatorial sun.