cbslocal – excerpt
WALNUT CREEK (CBS SF) – A glitch found in some new downtown Walnut Creek parking meters that left at least 100 drivers with unwarranted parking tickets has been fixed, city officials said.
Sensors near the new “smart meters” installed downtown last year are designed to wirelessly signal to the meter when a vehicle enters and leaves a parking spot, city officials said.
But some of the sensors were too sensitive, causing them to erroneously reset and prompting parking enforcement officers to issue tickets, according to Matt Huffaker, assistant to the City Manager… (more)
Or in the case of the sensors in SF, the batteries died.