In a recent post on Rowlands, 2009, I noted that it is common to find in the EC literature the view that when some thing is coupled "in the right way" to the mind, then the thing becomes a part of one's cognitive system. This, however, sometimes leads to the C-C fallacy. But, what encourages perseverance in the fallacy is, in part, how one understands "in the right way". For the cognitivist, "in the right way", means something like in the right causal economy of a computation. But, for Clark, for example, "in the right way" means something about "trust and glue". So, one might conjecture that part of what enables Clark to commit the C-C fallacy is not appreciating the difference between the two ways of cashing out "in the right way".
Again, this is more speculation on the source of the C-C fallacy.