You can also set pre-recording if using BI so the camera is recorded continuosly into memory and the system then records the memory section as well if a trigger is received. I use this on my cameras set to 5 seconds as often in my situation, the person won't trigger the camera until quite close and I might want to get the more distant activity. In the case of Fenders suggestion, the camera wouldn't trigger until the box was opened but the pre-recording could capture the person pulling up in a vehicle, getting out and walki up as well (depending on the pre-record length).