Changes in ignition system voltage or supply voltage to the detector can both cause laser falsing. So can a host of other things you'd never image. Example: 1988-1996 Honda Civic 4 cyl engines lived harmoniously with laser detectors until Honda made a running change to replacement distributor caps for these engines. With the new cap, laser detectors falsed uncontrollably.
I've also seen detectors triggered by activating a power seat motor in a C5 Corvette, windshield wipers in a BMW or by operating one in the vicinity of a nav screen (most cars).