It sucks that they take otherwise normal things and ruin them.Is it safe to use the OK hand signal again?
Capacitance detection is surprisingly precice and very repeatable form of distance measurement. eg: digital calipers/DRO's.
Yours is the best answer but my kneejerk gut feeling is: . Edit: The 'you' in this image refers to OP's parents.
The Australian equivalent got into trouble for trying something similar (without the flock integration) recently.Kmart too.
...through grey goo