You don't need to lock the software in practice. Your customers don't usually bother with redistributing what you're selling. With few exceptions, resellers (de

You don't need to lock the software in practice. Your customers don't usually bother with redistributing what you're selling. With few exceptions, resellers (designers, web shops, etc.) don't do so either. Basically, if your customers or resellers screw you badly they don't get to piggyback on what you're building. That's not to say piracy doesn't happen at all or can be ignored. You will find your software on file sharing websites eventually. But, quite frankly, it doesn't matter that much in practice, because free riders eventually come knocking at your door for support or an upgrade -- at which points you go "Mmm, I'm not seeing you in my customer list". And when they're students, they're really just learning how to use your software -- which you can view as free marketing. Source: I lived off of selling licenses for OSS that I was developing for about a decade.