FWIW, I've followed this pattern (one function is both decorator and factory) in my own code for quite a while.  I've never found it confusing nor has anyone else (that I'm aware) that has used those decorators.

One reason I've done decorators this way is because the empty parentheses are a visual distraction to readers.  They also imply to readers that more is going on than really is.  So I'm in favor of Raymond's plan.