This reminds me of "Leisure Suit Larry in the Land of the Lounge Lizards" - one the golden oldies

If you pirated a copy, ostensibly it allowed to play without any arguments. However, for the unlucky few who had the persistence to complete the whole game, the prize for finishing was that it asked you for your registration number, and whacked the MBR of your disk if you couldn't supply it!

One of the few remaining Mk1 owners... #00015