People are sometimes embarrassed or find it too aggressive to contact Executive Recruiters or any employment agencies with an email including their resume. They sometimes think is it more appropriate or polite to ask for the permission to submit it later on. The truth is that there is a chance your initial email will not be considered and you will then never get this permission.
Executive Search firms and recruitment agencies work all the same. They are contacted by so many people that you, as a candidate, need to be very clear and striking upfront. It is right that we want to make sure you can be polite, but it is not enough!!! We need to know right away what are your skills and previous experiences and obviously it is always a plus (or an obligation) to be polite.
ALWAYS attach your resume when contacting a recruiter for the first time!