Been a mechanic for 18 years and i certainly wouldnt dream of taking battery off to do a belt on 1, far to many owners dont know radio codes etc these days, then its sll your fault cause it worked fine when they brought it in,
I think it would cause more hassle than its worth,
But i see wher your coming from,
And op, no such thing as a cam belt sensor,
You've either picked them up wrong or something