I had a client last week in Melbourne who wanted to salvage some code from an existing SharePoint 2010 implementation. As long as it wasn't obfuscated, then I thought there would be no problems at all.
Red Gate's (previously Lutz Roeder's) Reflector is designed for just a situation - and I'd recently purchased the awesome VS PRO version (which is phenomenal lets you step and debug through other people's applications!).
However, when I tried to open up the assemblies in Reflector or on ILDASM, it appeared to indeed be obfuscated - by the Smart Assembly tool from Red Gate.
Typically, the obfuscated code will be shown with an error or garbled characters. e.g. "This item is obfuscated and can not be translated." - as below:
If you try and open it in ILDASM, it throws an exception as below:
However, if you open up the assembly with the new tool JetBrains dotPeek (the makers of Resharper), then you will be able to see the source code - even of those allegedly obfuscated methods and properties.
I'm not sure whether Red Gate deliberately set a flag inside Reflector when they purchased it from Lutz Roeder - but it seems like a few shortcuts were taken with the obfuscation engine.
So be warned - not all Reflectors and not all Obfuscation methods are created equal.