I'm not sure, but in several European countries the police is able to ask you for your ID when you're going about your business, there's no limitation that it m

I'm not sure, but in several European countries the police is able to ask you for your ID when you're going about your business, there's no limitation that it must only be in relation to an offence. Thus any interaction with them could result in you needing to put a stop to anything else you're doing as you're escorted back to your house to fetch your ID, unless you're carrying it in the first place. But the example I provided wasn't such an example, since there was a fine involved. However just having compelled ID changes even that situation. If Germany didn't have that I'd probably been able to just pay the fine on the spot without need to establish my identity. I don't believe there's anything equivalent to that in the US. Furthermore since there's no national ID system they don't even know if you have a driver's license, social security number or passport, so their options for compelling you to produce ID are limited.