have thought about a move, made up their mind, moved the piece, pressed the "submit move" button and then - and only then - realised they in fact wanted to move to the next square on...?

I've not done that, yet. I often end up click submit move, then moving on to a different game, with the memory of that game still in my memory. And I always am paranoid I missed something big, like hanging my queen or giving my opponent a mate in one. Err.

Well, I have had many instances where I had pressed the submit button, but then I realized that it was a blunder, but I was not able to press "Cancel" fast enough. I think they need to change that feature to make it easier to do.

ADK