It's not like a parking space where if I park in it, then it's unavailable for a handicapped person. There's someone's job to handle these requests and they have a limitless capacity. If anything, it actually takes less company man hours to respond to an asynchronous email request than a synchronous phone request.
I agree that it does feel a slight bit scummy, but after thinking about it I decided that I was OK with it. I can see how some others might think differently though.