For my own piece of mind, I called my attendants and explained that I had just seen a shady lady with a door opener. The person I spoke with knew who the girl was connected to in the building. Maybe I seemed nosey and paranoid to call and inquire, but it's better to double check, isn't it?
Who people allow to have access to their apartment is none of my concern. It's a free country, but some people make me wonder.....
When life is already uncertain, why would we risk our safety by being around unstable people? I'll never understand, but that's OK. I can't understand everything in life.