"ATL aren't striking- join them if you don't agree with NASUWT's or NUT's principles."
Thing is, I joined ATL because it was a non-striking union.
So I left it when it declared a strike last year, and joined NASUWT, because it was the only major union not involved in the strike at that time.
My head walks into my classroom at least once every day, to greet the children. She often pops in at other times too, for lots of reasons. It's a small school, and part of our way of working is that the whole school is everyone's domain - the only reason I ever shut my classroom door is if the front door of the school (right next to my classroom door) gets really busy or noisy and it is disrupting learning. The idea that other professionals should stop at my door and say 'well, I can't come in, I've had my 3 hours this year' is just absurd.
The idea that the head - or anyone, I get a lot of specialists in observing because I have some very SEN pupils and it's a rare week when I don't have someone in for at least part of a day - should be limited in the amount of time they come in to see the class is ludicrous, it's like limiting the amount of time my son can spend in the kitchen because I happen to cook in there. They're not judging me, they're there for the benefit of one, some or all of the pupils - are they happy, are they learning, do they need more help in some way, should I be adapting what I do to enable some children to learn better, or on the other hand need to tell me something which is of benefit to the children in my class or elsewhere in the school. It's not disruptive - the head is very respectful and doesn't interrupt, and in some ways the children are so used to it that their learning (which is the most important thing) isn't disrupted.
Believe you me, sitting next to your manager in an open-plan office in industry is far more 'intrusive'!