I've mentioned it plenty of.times before, but my phone has a call blocker which cuts off calls when I'm busy and sends a text telling them when to call back. It works very well and means not having some random decide for me with whom I'm going to have sex - punters don't have to feel ignored amd they can call back when I'm there to answer. I agree that the majority calling an independent will expect to speak to the person they're booking at least at some point.
If you're going to hire somebody bear in mind that if you pay them per day you might wind up out of pocket if it's quiet but if you pay per booking then they have a vested interest in getting as many through the door as they can because they'll be paid more, as with an agency pimp. And like an agency pimp, they'll be breaking the law.