My ID contains: first name, last name, date of birth, place of birth, length, issuance and expiration, document number, citizen service number (~SSN), citizenship, photo (2x), gender, issuing authority (in my case: a municipality so small that it's more specific than geoIP), and in some countries it also contains your place of residence.

If they just have my name, now they have a lot of extra information. That's why my government recommends[1] to both watermark the copy and blacken unnecessary fields like the citizen service number and your photo. Such fields don't help them identify you, so you shouldn't share it with them. But imagine actually doing that: the only non-black parts (the parts they can actually match against their database) would be my name. Or in the case of WiFi tracking: nothing. I had to submit ID but really they just looked up whatever MAC address I claimed; I could have claimed my ex girlfriend's MAC address for all they knew. It's also trivial to photoshop a document if all you need to swap around are a few letters.

Identification is completely useless unless done in person when they can actually hold the document against the light and compare it to the European database of what it should look like[2]. (I've never seen anyone do the latter; see also lichtbildausweis[3].) Online, the best you can do is ask to confirm data that you already have about the person. Asking to confirm that same data but on a photoshopped (watermarked and censored) piece of plastic doesn't help anything.

In conclusion, sure I agree that you shouldn't be able to request my data, but the point is about the means rather than the goal. Is providing a censored and watermarked picture of an identity document a means of reaching that goal a better means of reaching that goal than confirming some data like the calendar week during which I was in whatever hotel they have my data from (for example)? That's what GP was offering them: asking to confirm masked data rather than having to provide extra and unnecessary personal data.

[1] https://www.rijksoverheid.nl/onderwerpen/identiteitsfraude/v... In Dutch, but see the pictures near the bottom. This is the federal Dutch government's recommendation on how to provide a copy of your identity card.

[2] https://www.consilium.europa.eu/prado/en/search-by-document-...

[3] Original in Dutch: https://dewinter.com/2012/09/24/de-legitimatiecontrole-in-ne... TL;DR: a "lichtbildausweis" is the german word for "photo ID". But how many Dutch people know that? So when you order a photo ID from germany, for example from a website that sells company badges (like, upload your company logo and employee photo and they'll print a plastic card for you), make sure it contains all the fields that you'd generally expect on an ID card, and they'll take it for being a german ID.