A parent of my students (she has two kids in my class) came last Saturday 20 minutes earlier than class time (2pm). She knew perfectly I needed rest because I "accidentally" met her in restaurant around 12noon and I told her I had to rush back to rest so I could have enough energy to have my afternoon class. Not only that, I have a note on my front door, saying "Do not disturb between 1pm - 3pm unless class time". Nonetheless, she brought her kids came right after their lunch and knocked my door. And after I let them in, she said: "we are earlier." Not even a "sorry".
I was not used to make people embarrassed so I said that's OK. I quickly let kids playing with some craft sticks and told her that I must go back to upstairs to rest until class start. She said Ok. So I went upstairs and lied down in bed until a few minutes before 2pm.
I did not take this as big deal first but later last night, I was thinking it is a big deal. Not only she came way earlier last time, she ALWAYS comes to pick her kids late. Since her kids just started coming to my class about a month ago, I could not tell if this would be her "hobby", but this past Saturday gave me an alert that she could do this more often in future. So I made my mind that I should let her know that this is not "OK". I sent her an email this morning, asking her don't come that much earlier than class time because I could not afford to be bothered, and I appreciate her understanding.
I predict she would not be happy and will stop taking her kids to my class, which will be perfectly OK for me.
Thing is, as one of my friends mentioned, that I have some "luck" to meet strange people. Guess I do. Some of parents of my students are incredibly kind, but the proportion between these two ends seems to be a little out of scale. But of course, people like this parent are rare, but they can do huge damage to my life (I admit that my current situation is a bit unusual). So, lesson learned. The only thing I can do is to either they change their "hobby", or stop coming to my classes.