[bondarchuk]

"nobody will check passports"

"Those are random spot checks"

So there are random spot checks where people will check passports. So "nobody will check passports" is false.

[LtWorf]

Not "passport", valid ID. Which can be required also when not crossing a border, so you should have one.

[stavros]

Fine, word lawyer, "nobody will check passports above the base rate of passport checking you may get anywhere, including any random trip".

[dagw]

If you're going to risk your future permanent residency, it is very important to know exactly what that 'base rate' is. As someone who travels a fair bit within Schengen, I can tell you that the rate is quite high, much higher than it was a few years ago. And if you happen to look "un-European", the rate is quite a bit higher.