Basic human sociology experiments have proven that, whilst initially offering a reward encourages performance of a behaviour, once that reward has been offered the human mind ceases to think of an activity as enjoyable, and begins on some level to think of it as "work".
As a result, when a behaviour is being practised with the promise of reward, experimentation also demonstrated the products of such behaviour to be of a lower quality than those who engaged in the behaviour without the promise of reward - for enjoyment. Furthermore, when those who had been receiving rewards were no longer offered a reward, they ceased engage in the behaviour, however those who had never been offered such rewards in the first place continued.
In conclusion - Offering rewards for modders is more likely to inspire mediocrity and brevity in modding activities than it is innovation and long-lasting investment.
Second conclusion - Never offer your child a reward to be good. This will actually cause worse behaviour in general!