Two things:
1) How sure are we that the deer are hearing something...anything? And if they do hear it, how does a deer interpret the sound? Is it an unpleasant sound or something good?
2) Even if they hear something, what direction are they going to run? Their method of avoiding hazards seems to be an unpredictable and random escape/running pattern. If the deer is in front of you, will they run away from you or into YOUR path?
Until I can get better answers for these questions, I'll spend my money on improving my own riding techniques and fuel.