I guess this is a cautionary tale.
I was recently having issues with my Gmail account that's tied to my Epik ( a domain registrar ) account, so when I was supposed to renew my domain, I didn't receive any e-mails about it. When I decided to randomly check on my website, it seemed to be down. So I checked Epik and a domain that usually cost £15 a year to renew now cost £400 to renew as it was expired.
As a teenager who does not have £400 to spend on a domain, I decided to just wait until the domain fully expired and buy it for a cheaper price.
After some time, the domain fully expired and GoDaddy decided to buy it as soon as it did, and charged me £2,225 to renew the domain. I don't understand how a price that large is justified, considering that my website gets barely any visitors and I basically only use the domain for hosting stuff. No idea how hiking prices this much is legal
Neither do .dk domains, but in order to determine use the courts will have to be involved. I haven't heard about a lot of those cases, but I'd guess you can prove use against the person who wants to take the domain. If I have a domain called firstnamelastname.dk it'd be pretty easy to show that I got a mail address at contact@firstnamelastname.dk that's in use.