You misread my concern -- it has nothing to do with deleting your brain. My concern was if you are thinking an intentional thought "Write a letter to Gramma",

You misread my concern -- it has nothing to do with deleting your brain. My concern was if you are thinking an intentional thought "Write a letter to Gramma", and you had a passing thought of "Format and wipe my C: drive", I would hope the mind reading would distinguish between these two. Now if it is the same thought process as controlling a limb, well that sounds like the same mental energy needed to type out something on a keyboard or speaking commands, both of which happen at close to the same speed as thinking the words to begin with (well, talking definitely, typing within a high enough fraction for most proficient typists).