Tenants leaving basement/laundry doors unlocked and open

[Benjamin E.]

I have a nice updated 3 flat with a seperate basement where laundry is located. Someone has been leaving doors unlocked and open, which is not cool since there is storage down there. I have made repeated attempts to notify everyone to be sure and lock up. Everyone has responded that they appreciate the notice and that they are not the ones doing it. Thoughts? Auto locking doors? Cameras with a penalty for people doing it? Code locks assigned to people so I can see who it is? I really need this to stop.