Thank goodness this never happened to me cause my parents were good parents, it’s just as much the childrens home as the parents and children should be allowed to say “I don’t feel comfortable with another man or woman living hear” Its the parents responsibility to make sure their children are comfortable and feel safe around a new adult. The parent should plan a public meet and greet parent, child, step and after each one the children should have the right to say no more and it end there.
Depended case by case. Sometimes it was exclusive, sometimes not. Usually it was “the common areas in the basement are yours to use but not exclusively” whereas they wouldn’t be generally going upstairs. So I guess we could (and would) invade their shared space but not the other way around ha.
Fortunately only a few weirdos over the year.