> In practice EU people would be free to lie about when they arrived [..]
That's fine, until it isn't.
> You don't even need a passport, your ID card is sufficient for travelling inside the EU
I've slightly lost track of the scenario here. Are we talking about a hypothetical northern European who basically moves to Portugal without telling anyone? Is she registered as self-employed? Does she have a bank account? Does she have any dependents? Does she own a car? Does she have insurance? Does she still have a permanent postal address in the northern European country?
Are all those things running as if she were still living in her original EU country, and she's just in Portugal "off the books"?
They don't need to be registered, that's the point. Legally, yes, practically not.
Because you know, they are coming from somewhere, another EU country, where they have a permanent address, a bank account, a job even (they are just working remotely), a mobile which works for the first few months via free roaming, a car which they take back to their home country for the yearly checks, health insurance which is technically only valid for emergencies in another EU country (but if you are seriously ill you'll probably want to go home anyway)...
It may or may not work in all cases (for example, in Italy they like to confiscate cars with foreign license plates that are illegally staying there - don't ask me how they know).
But if you imagine an average 20 something, still living with their parents, but wanting to travel across Europe while working remotely, then today this is very easy and straightforward to do. Without telling anyone. Except their parents, of course :)
Portugal recently introduced a separate Digital Nomad visa.
In practice it's nonsense to pretend you can just turn up. You need access to the health service, you can't rent without a tax ID, your car needs to be insured, and so on. All of which require registration. And there are occasional ID checks, which will raise questions if you don't have a residency certificate.
So even if you want to live out of your car - which sounds like fun - you're still going to leave a paper trail and face some risk of awkward questions and perhaps a fine and/or deportation.
> Why would you need extra car insurance? Is your car insurance not valid for all of Europe?
Check the wording of your car insurance policy. I doubt regular car insurance covers moving abroad without telling them. Oh, and the vehicle registration isn't going to be valid either[0].
Let's say our hypothetical person has a car accident, a serious one, where the police get involved.
She was driving her (say) Swedish car, with [technically invalid] Swedish insurance, with [technically invalid] Swedish registration and number plates, they ask her for her ID, she shows her Swedish ID card [can't show a residency permit, she chose not to get one].
One big hole she digs herself if she starts lying to the police. A different hole, but a hole nevertheless, if she tells the truth.
> I'm not saying anybody SHOULD do this [..]
Quite
> but there are some people who definitely COULD.
(Not wishing to sound too old and grumpy) but there might just be a whiff of this sounding like it's the story of young privileged well-off types who can't be bothered to follow rules everyone else has to, thinking it doesn't apply to them, and expecting to get away with it when things go wrong? :)
As an example, I have seen videos of "house sitters" in Portugal that effectively "work" by staying at other people's houses while the other people travel, usually for longer periods, eg. weeks or even months. They water the plants, feed and walk the dog, make sure the property is lived in. They are not officially living there, but practically, they are. I was surprised that it is possible to make a living of this, but apparently it is!
That's fine, until it isn't.
> You don't even need a passport, your ID card is sufficient for travelling inside the EU
I've slightly lost track of the scenario here. Are we talking about a hypothetical northern European who basically moves to Portugal without telling anyone? Is she registered as self-employed? Does she have a bank account? Does she have any dependents? Does she own a car? Does she have insurance? Does she still have a permanent postal address in the northern European country?
Are all those things running as if she were still living in her original EU country, and she's just in Portugal "off the books"?
If so, wow. Good luck.