I've asked this many times, but I phrase the request differently. What I usually say is, "I'll be requesting a Time Out if he makes the Free Throw." Then I make sure I call it as the ball goes through the hoop.
I can appreciate the comments made about not wanting to blow the whistle and grant a time-out without hearing the request at that specific time. While I'm sure it can be explained calmly to an opposing coach that the request was made before the free throw, why put yourself in that position?
By the way JRut, why are you calling me paranoid? I know you are out to get me and hurt me. Just like all the others!