Didn't know that about the Carnatine. I got 'em cheap off of eBay, and at the time, every routine I was reading about, on a variety of different sites, were almost universally including it as part of the supplement package - so it wasn't just one site trying to hawk their shit (cough cough, bodybuilding.com, cough cough).
As for the scale and BF%, agree 100%. I totally know it isn't 100% accurate, but at least gives a trend. Everytime I get disciplined in this, I always weigh myself once a week (usually Sunday or Monday), after 1 cup of coffee, and my morning movement.