The main reason I dont do fees in an email right off the bat is because I find that the first and only question coming from them in the first contact email is "what are your rates" . I generally respond first by asking more questions about what theyre needs are with respect to hours or if they need full time or part time etc. My full time rate is different than part time. I explain that this information is needed to properly quote them a daily rate and that I would prefer to disuss it over the phone or in person.
I see what your saying about what the perception might be though.