Repeated false alarms

Years ago, my ex-wife had false alarm problems with her VW Cabrio. After this went on for months, we finally realized that it only occurred when it was rainy / foggy outside. We were still lost as to what was causing the problem until one day, I was just getting out of the car (it was raining) and after I shut the door, I realized the interior light was still on. I figured I had just left it on, but when I checked the switch, it was off. I just happened to notice at that moment that the door plunger switch boot was a little dry-rotted. Finally, it dawned on me; I took the boot off of the switch and sure enough, it was corroded and the moisture was making the switch contact even when the door was closed.
If you are having the same / similar problem it will never false alarm if it is stored indoors, ie, at the dealership's shop. Have them check to see if all your connectors and switches are staying dry & clean especially in times of high humidity. Simple things like that can make a car totally wonky.