Also:

On the subject of providing GC versions of shaders in commercial products, surely there would never be any need to distribute modified shaders. All that's required is the Python script to modify them to include the GC nodes.

Even if some product shaders are too complicated to have GC injected by a 'generic' GC injector script, a specific injector script for these shaders could be written by someone who has the product and can see the node structure and names. 

To take this one stage further, a single injector script could GC a complete texture set for an outfit, or whatever parts of it are actually being used.

No?

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)