Chabot always gives a full effort, insane anyone would question that. He's prone to brain farts, but I've never questioned his effort.
To add, we can't lose sight of increased odds for more 'brain farts' the more minutes one plays. That is even more the case when he is over-played. I believe he is playing better this year, at least by my eye chart. Last year it was constant mistakes, not just an occasional one. He appears to be controlling the game much better this year.
I am more concerned about Sandy but I believe part of that to be not being paired with a better partner. You can't partner a 5-6 D (being generous) with your #1 and expect him to hold sway as such.