Question About OS Install & Default ME Behavior

I want to preface by saying I know that it's hardware-agnostic - not exclusive to Windows - but I feel like it may be safe to say it's most commonly used there? (I'm super open to being corrected if I'm wrong!) Anyway, I have a question about the Intel Management Engine, or at least other people's experiences with one aspect of it. 

I guess I am curious as to whether or not wiping and installing a (legitimate version of) Windows will have any impact on the ME? I initially thought it would, but because it doesn't care what the OS is doing, I began to think maybe not? 

My bigger question is about whether or not the ME should have/could have been enabled and the default password already changed, or whether that is something that would have had to have occurred after the OS was installed. 

And my last question is more to try to verify an assumption I am making - that if a change was made to to the ME, post install,  that it would have required physical access?