I'm glad to read that I'm not alone with this!

I have signs on doors to alert people that these are indoor cats
I have such a sign, too, but still people tend to stand in the open door to talk, something I really hate. But people like my landlords are too old to keep in mind that there are cats that will leave the apartment when the door is open.

One or two years ago, I got a real shock when I got up one Sunday morning and found the apartment door open, and the cats gone. There was a storm that night and I guess the wind has pushed the door open. Luckily I found both Lily and Luna in the stairway, but the very next day, I fixed a hook to make sure the door cannot open again.

Kirsten