I got billed for an "office visit" to the tune of $79 by one of my doctors because he TALKED TO ME during an ultrasound he was doing. He billed again (another $79) for the office visit the next day to discuss the tests, results, and my treatment plan.
I called and complained, and their billing manager literally asked "Did he talk to you during the test?".
I had another doctor charge me for a full office visit ($80) for me telling her my symptoms, and her giving me 2 phone numbers for other doctors. I was out of her office in less than 5 minutes. There was no attempt at diagnosis or treatment (unless you could "Yes, that sounds like a problem. Here's a couple of other doctors to call" as acutal medical care).
I have no problem paying a professional for their time, but they were very clear on the purpose of my visit ahead of time, and instead of just referring me to another doctor over the phone, they wasted my time and money making me come in and pay $80 to hear it in person. I found another doctor.
So, it's not just limited to the financial field. Pretty much any professional can run afoul of this.
Bottom line, if I'm being billed for someone's time, I want to know ahead of time and have the option to accept or decline. I don't see what's so hard about presenting a client with a statement of charges during the initial consultation that clearly states rates and billing policies for phone contact.