Try This One Weird Trick Russian Hackers Hate
In the 90s I used to make money off shareware, and every time I release a new version hackers would release "cracks" for the license key. Eventually I figured out that these cracks are coming from Russia.In the next version of my program, I added a check for system language, and if I detect Russian then I bypass the license key checks, and the program is free to use. This stopped hackers from releasing cracks.