If they were my modules I certainly wouldn't be happy if I spent countless hours writing modules that are essential to the workings of my programs, released them freely, then subsequently discovered third-party competing programs based entirely off my work.
Then you also have the legal costs to shut down said infringments... and the posibility that such disputes won't outcome in your favor.
a paid developers license that specificly outlined what can and cannot be done with them would be the only way to go. this way you also can keep track of who as legit access and such.
just my 2 cents ;-)
Limecat is not pleased.