I still wonder what the legalities of this sort of lifestyle are? I tend to assume they don't face problems just by virtue of lack of understanding and it being fairly uncommon?
Most regions you tend to be allowed to stay 3 months in a 6 month period on a tourist visa, so as long as you aren't overstaying, you are fine.
The only problems you would face are when leaving a country, if you overstay you may be not welcome back and/or fined.
On entry to a new country, the border agents will be the judge if you are welcome or not.
I think grandparent's question is legitimate. In most cases the authorities probably don't care much how tourists (or, people with tourist visas) spend their time, but I also wonder if all these nomads follow the letter of the law to the dot -- which would be a feat with the laws of 78 countries.
Things become more complicated if you decide you want to stay permanently somewhere while working remotely. Then it depends on the country and how much crap you're willing to put up with.