Without a running legal system we do not have FLOSS, neither the Free, nor the Libre, nor the Open Source Software. Only if the four rights have successfully been granted to us by the respective licenses, we have, what we want to have: free accessible software. But for preserving these rights we must thoroughly try to fulfill the conditions these FLOSS licenses impose on us: You can’t have the cake and eat it.
Sometimes the nature of the FLOSS makes our compliance life miserable. We have described that in a specific post. Here are some additional irritating examples:
modernizr is a set of functions which is compiled by a configuration process and offers only a short header with a small hint to the MIT license. This header does neither contain a copyright line nor the license text itself, the corresponding license page does not contain an adequate copyright line.