IMO, it would be counterproductive to employ any kind of obfuscation or license protection. Having access to the code is part of the reason people choose to build their sites on WordPress. More installs than not have some kind of customization done. Plus, you'll have less satisfied customers (inevitably a significant portion will have issues getting the loader/licensing setup to work on their shared host, or will have other issues you can't help them with because they can't debug the code) so less blog writeups / recommendations driving referral sales.
I was in the WP business for a while, with about a quarter million in sales before I sold it off, and did nothing to prevent piracy. It wasn't an issue. Someone pirating the code doesn't hurt me. Anyone that wanted the plugins/themes and had money was going to pay for it, as that's the only way they would get support and updates.
I was in the WP business for a while, with about a quarter million in sales before I sold it off, and did nothing to prevent piracy. It wasn't an issue. Someone pirating the code doesn't hurt me. Anyone that wanted the plugins/themes and had money was going to pay for it, as that's the only way they would get support and updates.