There could be a requirement that app store listed apps need to include some sort of audio watermark. While that wouldn't be perfect, since there will always be

There could be a requirement that app store listed apps need to include some sort of audio watermark. While that wouldn't be perfect, since there will always be ways around it, this would still raise the barrier significantly and cut down on much of the abuse. Most criminals are lazy and/or not very tech savvy. Raising barriers and prosecuting the worst offenders cuts down on all sorts of malicious behavior that is technically feasible.