A hidden threat in this, is that podcasting can look like journalism to many economies. If you "report" on current affairs in any way, you can fall into the trap.
Mainstream broadcasters are always super-careful when staff are sent to the USA, to get the right visa. If the staffer just goes to the USA, they have to make damn sure they don't return to work, even if they take that call about some story, there is a risk: If you entered the US on a tourist visa but always intended interviewing somebody, you're working as a journalist.
They can, and do, chuck you out of the country. And returns get hard once you have to say YES on the forms about "...have you ever...."
I don't think the USA is unique in this regard. Lots of economies, western, democratic, and otherwise do not want people to casually "just do it" -you need to front up about what you do sometimes.
I always thought that a "tourist" visa allows you to do "work" for your non-US company, it just prevents you to from "working" for a US company, or being paid by a US company for work done during your visit.
I entered the US dozens of times on an ESTA for work reasons, I always declare I'm there for "business", offering detail if needed, and never had any issue.
As you'll find if you dig into visa regulations in many countries, the definition of "business" (activities usually permitted on business visas or visa waiver programs) is typically a lot more detailed than just whether the company paying you is in or out of the jurisdiction.
This is why my employer's internal immigration processes, even for short-term visits like conferences or whatever, present you with a comprehensive list of different categories of activity you might be undertaking to determine whether you need a work permit or not. It's annoying, and our internal immigration systems are very, very much imperfect, but I can see how it came to be.
Because of force of habit. I work for a NFP with membership of China and Taiwan, and we have to steer a narrow course around calling places countries or economies. I got used to this habit.
Somehow journalists make headlines when this happens. Lots of people enter on a tourism visa and do not earn income but are in the us for a mixture of reasons -what gets reported, is journalists being caught and expelled.
I have an APEC card. I only ever enter for work. I think it's considered ok to recreate, having entered for work related reasons.
This is true in general for digital nomads, whether they blog/podcast or even just freelance, a lot of whom continue to work a few months at a time in foreign locales on tourist visas. I've seen their blogs refer to visas as a gray area. I'm pretty sure this is a mistake.
I've looked at a few of the digital nomad guidence sites and none I've seen do much more than say its vague. If Steven King goes to the UK and writes a few news about his book, is he working? If I visit the Uk from the US on vacation and I answer a work email using my phone am I working? Probably these countries don't care, but where is the line between answering an email and "working" while living in the uk in a hotel room for a month?
I've never worked anywhere but the us, but as a dev I could work remotely anywhere in the world if I was certain it wasn't illegal.
I got permanent re-entry work permitted for Uruguay at very low marginal effort. It's not bali-cheap but it's developed, different, gateway to all of south America, and high tech friendly.
There are economies which would welcome you as a digital nomad.
entering the UK under a tourist visa or waiver program, you must be able to fund your stay. The tourist visas are No Work or Recourse to Public Funds. If you are funding your stay in the UK by working remotely, you are not abiding by the terms of your visa. This isn't the same as getting an emergency call out while on holiday.
How does the border agency know? They ask you a whole bunch of questions upon entering the country. So if the plan was to work remotely you'd end up lying to them. Digital Nomads calling it a grey area is often a nice way of saying "unless you tell someone the truth, you'll be fine"
If it's something you plan on doing, I'd highly recommend knowing the regulations for each country yourself and not relying on a third-party website to tell you things. That way you decide what you say to whom and what risk you take.
Define "living." As a US citizen, I've gone over to the EU, including the UK, for multiple weeks to attend multiple conferences, have customer meetings, etc. I've never been anything but 100% upfront in answering any questions about the purpose and duration of my visit honestly and have never had an immigration official so much as blink at my answers.
I know that some countries (such as China) do require business visas for attending a conference and I've to get letters of introduction, etc. in order to get my visa. But it's never been an issue in Europe.
Mainstream broadcasters are always super-careful when staff are sent to the USA, to get the right visa. If the staffer just goes to the USA, they have to make damn sure they don't return to work, even if they take that call about some story, there is a risk: If you entered the US on a tourist visa but always intended interviewing somebody, you're working as a journalist.
They can, and do, chuck you out of the country. And returns get hard once you have to say YES on the forms about "...have you ever...."
I don't think the USA is unique in this regard. Lots of economies, western, democratic, and otherwise do not want people to casually "just do it" -you need to front up about what you do sometimes.