100 mA draw is not enough to kill the battery overnight. That battery should support 100 mA for at least 25 days. Its something else. I have a similar problem on an '06 9-5. Twice, taking it to a glass shop to fiddle with the driver window lift, within 30 minutes it would not start. Not sure but maybe the headlights did not turn off. A real possibility related to the switches in the ignition lock. Combined with a substandard battery. I use AAA (auto club) batteries because they come to me and replace under warranty.