Carbs burned? That makes zero sense. If you're actually restricting carbs to the point advocated by most of the low carb books, then you're not burning carbs on the treadmill, you're burning fat for energy (aka ketosis).
It is 100% pointless to count carb grams burned, since you can't "undo" carbs ingested. Even if you intake 80g of carbs and then subsequently "burn" those 80g, your body has still produced the insulin to convert them to glucose (which is the only way your body can use them). And minimizing the body's insulin response forms the whole basis of the pro low-carb camp's argument.
Also stupid since (as Gobadgrs pointed out), there is a simple linear relationship between calories and carbohydrate grams... it's not rocket science. Plus, even calories burned is a rough estimate based on a few basic variables.
Ugh, you know idiots will fall for it too, because it has the word "carb" in it.
Sad...
l2c