If you counterfeited directly from a Feed, it would be noticed sooner or 
later, because all matter compilers fed information back to the Source. You 
needed your very own private Source, disconnected from the Feed network, and 
this was a difficult thing to make. But a motivated counterfeiter could, with 
some ingenuity and patience, put together a Source capable of providing an 
assortment of simple building blocks in the range of ten to a hundred daltons. 
There were a lot of people like that in Shanghai, some more patient and 
ingenious than others.