Ensure legal copy of video

I have someone creating videos with camtasia studio. Although they say their copy of the software is legal I would not like to have videos created with pirated software and have the videos I need confiscated.

So my question is, how can I ensure the videos in avi or flv format created with camtasia studio are legal?

Thank you


There is nothing you can do to verify this. Even if there were a watermark in the headers or something (I doubt it) it could easily be removed even simply by re-encoding it with something else farther down the line.