Possibly by using a password for the gates or maybe adding only the res+ members of your town to be able to activate the gate. Then again a builder could just grief their way in if that's what they have their mind set on or somebody could just forget to close the door.

 

You can use the /cmodify command on anything you use the /lock command on.

/cmodify alialbatros

That would allow you to open the locked door or chest I used /lock on.

 

If you use /cmodify g resident then /cmodify g mayor then /cmodify g president anyone res+ can open it

 

Really? That's cool.