If you have an e46 OEM alarm system, does the system trigger when armed and you put your arm inside the car through an open window?

I did a self-install in my 2005 330i ZHP sedan (very easy), and then recently had Tischer activate the alarm when my car was in for INSP I service. The panic button works on the key, and the alarm also triggers if you leave the hood popped then arm the system and go to actually raise the hood. I put the interior motion sensor portion of the kit in the roof, but it still doesn't trigger with the arm though an open window test.

Am I not testing this portion of the alarm correctly, or is this more likely an issue with how the alarm was activated? Thanks.