What happens if someone modifies software under Fair Source License and redistribute it ?

[dgpv]

Will that person have the right to collect payments from the companies that use the modified software, and exceeded allowed user limit, or original authors still can charge these companies ?

What if the person does not simply modifies our software, but just takes a small portion of the code, and uses it in new product ?

Do original authors retain the right to charge companies that uses such product, on the base that it uses a portion of the their code, and therefore is a derivative product ?

Even if original authors retain the right to charge such companies, can the person who created a derivative product change the license to raise the user limit to one million users, for example ?

[chadwhitacre]

Closing in light of #9. 🙏