🚀 go-pugleaf

 
I need help designing a "tow" sensor to add on to my existing car
alarm.
 
The car currently has a shock sensor, but towing the car would not
necessarily set it off... it reacts mostly to higher frequencies,
like the car body getting hit.
 
I can't use an ordinary tilt sensor either, since if I park on a
hill, it won't work!
 
Anybody have any bright ideas?  I was thinking of something that
would kind of react to a change in tilt.  Maybe something that would 
automatically level out when I parked on a hill, but would trigger
at the faster lifting of the vehicle by a tow truck.
 
Or maybe there's a better way of detecting a towing attempt?