I have always believed than any decent alarm system would tell you exactly which sensor was tripped, so this looking for the open door stuff made no sense. A really good one would probably save the time and date of the past 100 events. Feldman, please surprise us!
Their alarm would tell you too, according to the question Dusek asked BVD, she agreed but she went right on telling how she searched for it.
Hopefully, DVD's little magnet trip didn't mess up the sensor/alarm recording data.