<p>I don’t think I’ve ever lived in a house with bedroom door locks, but I did put a hook and eye lock on my bedroom door when I was a teenager. I got tire of my younger siblings walking in when I was dressing, studying, etc. but because the door never shut tight, to keep out the Great Danes who could just push the door open and scare me to death. My parents were fine with that.</p>
<p>Except for when my kids were little, I have always knocked first. Agree that it’s just common courtesy. Even if I had nothing to hide, I wouldn’t have liked it if my parents felt my room was not my sanctuary that they could just invade at any moment, so I let my kids have their own spaces.</p>