Put a lock on the gate only you have a key to. Either they'll get sick of asking you to open and close it for them and develop some common sense or you'll be aggravated by the inconvenience, but sure your dog doesn't get loose. I believe in tough love, lol. "You can't be responsible with a gate? Fine, then I'll treat you like a bunch of kids, install a lock, wear a key around my neck, and you'll have to ask me to let you in and out."