🐧 How exactly are royalties enforced on HEVC licenses?

I really had no idea where else to post this, would appreciate it if I could be guided to a more appropriate sub for asking this question, in case this is inappropriate.

I understand the hardware implementations of HEVC, as I am guessing it's pretty clear that if a chip on a device were to include hardware codecs, it would be pretty easy to keep a count of them (since they would be produced in bulk). But how exactly do you get a royalty for software implementations? Technically, given the resources should I not be able to create a software implementation at home?

According to the wiki, software implementations no longer need to pay the royalty as of 2017, but prior to that how exactly was this even enforced?

Is it even possible for someone to implement at least a basic variant of standard codecs at home?