If you put commercial license and a free license, kids that don't know what license is but still know how to sell using their daddies's paypal accounts will most likely violate the free license with their indie games.
I mean that nothing technical can stop a human. You, other developers and your lawyers. They enforce the licenses. Ana every company needs them. And it never, never ever works as expected. Look for example Microsoft Windows... Here, in Bulgaria, almost all people use pirated Windows. The laws in Bulgaria are bad, they protect the home user's freedom more. If you are company, however, they will sue you if not licensed. And, ISPs won't assist you if you want to sue some unlicensed home user that used pirated construct then sold his game and gained more than Scirra... Eh, in most cases, these guys pay soon or later ;] But that are also the facts.
So when you allow commercial exporters, this is good. Only the exporter's author must think well how to handle these cases with pirates around and not to screw up when they come and tell him "hi" ;] Because they come. If a product is a success.
As a game designer, I try all these gamedev tools out today. Game Maker, Multimedia Fusion and Construct. Every one of these applications have its pros and cons, and every one is well-suited for some users. I like the idea of Construct, I find Construct better than game maker, but I find it also more hard to use than Game Maker for some things. Well, in fact, I don't like Game Maker at all! So you must focus in creating Construct AWESOME! Not like Yoyo Games. They want the money, like M1cro$0ft. Every major update of Game Maker is nothing! Nothing, except new DRM that gets cracked on the second day after the update. Construct must focus on usability and features to get cool! And it is, even in its beta, better than game maker. Of course, the best solution is C++, or writing own game engine (which I am doing now, by the way), but not everybody can write such a tool :)
Sorry for getting offtopic ;]