Depends who you talk to, really
In all honesty, I'd wager that the vast majority of people who go 3000 miles between changes don't actually change their own oil, but rather pay a Jiffy Lube type place to do it, and thus never even open their hood in those 3000 miles.. unless they've broken down on the side of the highway or similar.. and thus they would not have added any oil to the engine if it was a quart low. In fact, they would not even know it was a quart low. They would find out once it was a lot more than a quart low.. on the side of the highway.
On BITOG, however, you're likely to get an entirely different story. I, for one, check my oil numerous times during my 7,500 oil change interval, even though it does not leak or burn any oil, just to make sure I'm aware of any changes.