Please look at the following two definitions of "none the wiser":Not exactly. It means that the public never noticed that the substitution had been made.
Didn’t I say that?
It seemed a bit odd to me too. "Unclear" is perhaps a bit too strong, but I feel it would be clearer with "not" moved five slots along:I was referring to your "had no reason to believe" comment, which seemed unclear to me.
For the record, this Brit isn’t familiar with “never the wiser”.Hmm... The second sense in Merriam-Webster might not be very common in BE. I'd like to see the definition in OED.