There aren't many ways to enforce that even if it did make sense. Personally I think C2 is dirt cheap for what it is, especially during the early adopter period which lasted for mooonths. If not, well, wait until a competition I guess, licenses are given out all the time. If not, well, suck it up and spend a little money XD GM is charging like $150 just for a single exporter and I hear they're buggy as ever.
With exporter to PC and with full features - $39.99 (this is the old version 8.1). With it you can make masterpriece games if you have the skills of course.
The newly Studio Standart version with exporters to Mac and PC - $49.99.
The Professional version which have half of the available exports remaining is 99.99$.
The Master version with all exporters is 499.99$ which is cheaper than buying Studio Standart + all the exporters or Professional + the exporters.
If you talk about the exporters alone - yes they're expensive from 99.99$ to 199.99$. That's why there exists Professional and Master editions.