Licensing for Illustrator Extension

I'm about to release an extension for Illustrator and have been looking up ways to help protect against piracy. I've been wanting to implement some basic license key check at the initial launch of the plugin, and am wondering if there's a way to implement that and maintain my ability to sell the plugin on the exchange. Does adobe do any kind of validation check for a plugin once it is purchased and installed? Is there a way to implement a license key check? Or would somebody just be able to share my plugin without any hurdles?