David Skelly wrote:

reverse engineering it could be a breach of the licence terms (which normally forbid that sort of thing)

Perhaps this could be the reason exactly why they forbid reverse engineering? :-D

Additional bonus info: The underlying size of an enum can be declared in C# (and, presumably, in the other .NET languages as well) in the same way the Microsoft compiler allows enums to have a defined size in C++. So an enum value isn't always an int.