Instead of continuing the battle against spammers, we decided to close the forum for new users
and topics. But don't worry,
there are still plenty of ways to reach us. Most notably, we will move our attention to Stack Overflow,
where we will monitor questions under the tags [highcharts],
The email just showed an example of where to put it in the page source code - directly viewable to anyone that decides to copy it. Do you have a way you can check to see which sites use the same licence key? - If you set up a database for your unlimited licence customers to be able to log in and add the domains of the sites they have used the script on, any stolen licence codes would stick out.
I'm not quite sure how this works either... I keep my unlimited license in a .txt in the root directory just like the email said. What's to prevent anyone from doing http://saidsite.com/filename.txt and getting the license and using it on their domain?