Create a sample Android module and build it. Then follow this step by step.
1. Extract the contents of the zip file inside the dist folder.
2. Extract the JAR file obtained from the zip file.
3. Use JAD (Decompile tool) to decompile the any *.class file.
You will observe that the entire source code is displayed. There is no obfuscation. I think Appcelerator must provide an obfuscation procedure during the build process.
If any such process is present (using ProGuard for example), then can you please let us know. If no such process exists then it will be a great idea to add this feature. This will increase the security and also reduce the module size.