🚀 go-pugleaf

Yes, motion sensors do cause false alarms.
Yes, they can detect tow-away or "bump" situations.

The best set-up for use with a motion detector is to hook it to a
Page Alert alarm (or equivalent).
The Page Alert will basically notify you of an alarm by beeping
a little pocket pager.  That way, if your alarm falses, you will
will be the only one alerted (kids like to bump cars with motion
alarms in order to get the owners to turn the system off -- or
be killed by their neighbors).  Not only that, but you can check the
situation out and either call it in to the police or "handle" it
yourself, depending on your abilities.

The Page Alerts are very inobtrusive, which is why I wish most car
alarms were made that way.