Does ”My house, my rules” go for older parents living with an adult child, like it does for an adult child living with parents?

su

I was partly inspired for this topic by a post regarding an adult child living at home, whose mom said she must wear a bra when her boyfriend comes over. The comments were pretty divided.

When any topic regarding an adult child who lives with their parents, who dislikes a rule, A LOT of comments are along the lines of ”Their house, their rules” basically saying that even if you are an adult, if you live with your parents you still need to follow their rules, you are still their child and must respect them. In one of my last post on my 18yo friend, who lives at home, parents putting app blocks on her phone, a good amount of comments were along that line too and it got me thinking.

So, for those who believe in my ”house my rules” in regards to adult children, would you also say the rule applies for when an adult child lets their older parent live with them? Let's say an older parent moves into their adult child and son/daughter in laws home, and is financially dependent on them. Should they follow the rules the same way an adult child living at home would? If the child asked them to where a bra, or not use certain apps or media, should they?

If you don't believe in ”my house my rules” what should the compromises me in both situations?