It's not really the end of the world if only some people pay for your software. You could charge for binaries but let people build from the source. You are will

It's not really the end of the world if only some people pay for your software. You could charge for binaries but let people build from the source. You are willingly giving people the freedom to redistribute those binaries, such as to their friends. It's just not an issue. It's not a crime that needs to be prevented.