I'm not so sure how smart it is to automatically arm a system based on time alone, especially if your system is monitored. This is even more true for a Night mode and thats all I would use at bedtime. If an intruder trips a perimiter opening, I want to know immediately, not in 30 seconds. So, assume you auto arm the system to Stay Night mode at 11PM, but you happen to be out that night. You come home after 11PM and you have no way to get in the house without tripping the alarm. Or, you are out really late and have a babysitter. The babysitter either doesn't know or forgets and steps outside and trips the alarm.
Anyway, my point is either build in some smart exceptions, or just press a button when you really want the system armed.