Recently at an OSM meetup with the local government in Aachen (Germany), they mentioned that some imagery they shot was deemed too invasive and only used internally. I thought that was 10cm, but now checking what is available, looks like I was wrong! Probably it was 5-7cm then? Or maybe this was rather about the imagery available from different angles, so you can see into gardens from different directions?

In iD I see that indeed the PDOK imagery is now labeled 7.5cm, but checking that against the Belgian and German 10cm:

PDOK 7.5cm: https://snipboard.io/fbWqYM.jpg

AIV Flanders 10cm: https://snipboard.io/Ahn4lJ.jpg

NRW (Germany) 10cm: https://snipboard.io/RpT3vA.jpg

PDOK's looks awful, much worse than 10. Maybe some regions are available in a higher resolution?