Sorry - I wasn't able to convey my thought. There was no reason for the C# compiler to include the source code into the binary. Into the debugging symbols (which is a separate file) - maybe..?
Anyway, I went ahead and compiled a debug app on .NET 1.1. The binary does not include the source code. And neither does the PDB. It includes a file path to the source though ("Visual Studio Projects\ConsoleApplication1\Class1.cs").