I have met very few teachers in K-12 for whom that was not the case. Most of the ones for which it was not were WWII veterans.
Friend of mine with a PhD in education and 40 years as a teacher bemoans that situation regularly. I find it amusing that when shown a shackle he was unable to identify it.
Why is it so important to you to believe that teachers know anything about anything other than the theory of teaching. Or are you one of those poor deluded fools who thinks that because _his_ kids get good grades the schools are doing a good job for them and that it's all those _other_ schools that suck? Or perhaps you are a teacher and your ox is being gored?