Unsocializing my homeschoolers

We are a homeschool family. Like every other homeschool family, we do what works best for our family. We are not the family that gets up at 7:30 every morning and finishes school shortly after lunch. We normally START school after lunch time. Because of that, we are often not finished for the day until 5pm. The children in our neighborhood all attend public school. I have had a hard time getting them to understand that just because they are home from school at 2:30 does not mean my children are free to go play. I tend to get very impatient when the little boy down the street rings my door bell every twenty minutes just to ask "are you done yet?" When public schools have a day out does not mean that we will not be doing school. There is one little boy in the neighborhood that has told my kids that they do not have to do school and can come and play because there is no school that day. This same little boy feels that it is ok to ring my door bell at 8:30 am on the weekends. With the hours of Monty's job and me doing a paper route in the middle of the night, we DO NOT get up at 8:30 on weekends (or most any day!). I also do not like for my children to play with the neighborhood kids everyday. These children are outside from the time they get home from school until the sun goes down. I believe playing outside all day is great but I don't know when they ever have any family time. When my kids are with their friends every single day, problems arise in our home. They start to focus purely on their friends. They start talking to me in a way they know not to talk to me in. They fight more with each other. The family relationships we work so hard to preserve seem to go out the window fast.
I had to find a way to UNSOCIALIZE my homeschooled kids. A way to keep the door bell from disrupting our school time. A way to keep the door bell from disrupting our family times. I decided to make a sign for the door that was simple enough for even the 6 year old neighbor boy to understand.

This is now what they see as they step on to my porch. I hang this sign on the door at night and leave it there until I decide my kids can go outside(in the front yard) and play. They are still able to go in the back yard because we have a privacy fence. When I feel that me kids have had TOO much friend time, I just leave this sign up all day long. We can often hear little boys on the porch reading the sign but we never hear that door bell ring! That may be because Keslee asked me what I would do if they rang the bell anyway and I said "I will just whoop their butts!" Keslee told them all what I said. Of course I would never spank them without their parents permission (even though a few of them really need it) but as long as they think I will-I don't have to worry about that door bell!