I like that the surface goes to sleep/connected standby when I don't use it for a few minutes. I'm in a lot of meetings and this really helps extend the battery duration. However it's a bit annoying to put in the (picture) password each time it wakes up. I'd like it to wake-up without needing a password if it's been asleep a shorter period (i.e. I assume i'm nearby but just have not touched it in a few minutes) and require password if it wakes up from a longer sleep period (e.g. 20 or 30 minutes). Is this possible and how would I do it?