I feel that would be really unnecessary and possibly harmful to the MOOCs themselves.

1 - Sign ups alone require nearly no resources from the provider.

2 - Attendance and therefore popularity could be much lower. While that could be a good thing (less people and more money -> more support to each student), it would probably never be enough to cover a course's cost.

In the end, people are learning. I haven't completed any course yet (attended about 4, attending one now), but I'm thankful for them and I don't think the resources I used harmed the MOOCs.