In my family of origin only aunts (siblings and wives of siblings) and uncles (siblings and husbands of siblings) had that "aunt/uncle" title. (SIDENOTE: some cultures have different titles for aunts/uncles by blood vs. by marriage - just saying - and may also differentiate by maternal and paternal lineage.) Some of our friends use "Aunt/Uncle" for family friends that are close enough to correct or reprimand poor behaviour.
In my family, "Auntie/Uncle" was used as a term of respect for family friends as well. It was mandated, to the point where, when my mom was dating, my grandmother insisted I call my soon-to-be dad "Uncle Al." He HATED it. Lol...
I was 5 at the time, and in no way confused re. his role in my mom's (and my) life. Kids are pretty smart.
PS. I don't want anyone dropping by my house unannounced, ever. Unless you actually live here, you seriously need to ask!
THIS! I'm probably about as extroverted as a person can get, and my home is still my sanctuary. I'm going to be extremely put out if anyone starts pulling a Kramer.