Learn English – “Soft-peddle” vs. “Soft-pedal”: eggcorn blunder or sly play on words

In chat the other day I asked the following question:

"Recently I've been seeing writers using "soft-peddle" in print (in reputable publications, to boot) when I am certain the trope is "soft-pedal": anybody have an opinion on this?"

My reasoning is that the term comes from the soft pedal of the piano, which the musical among you will recognize as being the pedal that composers want you to use to play a passage quietly and without force.

@tchrist noted that the OED only lists "soft-pedal": "OED attests all three of soft pedal, soft-pedal, soft-pedalling, but not the other." @BarrieEngland agreed, and said he thought "soft-peddle" might be an eggcorn of "soft-pedal."

Further research on my part yielded information that "soft-peddle" is even included on The Eggcorn Database, a Web site I hadn't known existed till now. The term soft-pedal when spoken might be thought by the listener to be related to the "soft sell".

The use of soft-pedal peaked in the middle of the last century, while "soft-peddle" began around the same time and gained a bit of currency since then, though it is still seen far less often — overwhelmingly so — than its forebear.

It gets down to this: Are we seeing a play on words or a blunder? Certainly someone with sufficient writing credentials could be given the benefit of the doubt. Yet it seems that even (or especially) the best writers might want to underscore such a subtle pun with quotes, or set it off some other way that suggests it wasn't just a typo or brain cramp. And if "soft-peddle" makes steady gains, might it not one day supplant the term that spawned it? Bonus points for anyone who can provide at least a single documented instance of "soft-peddle" being used unequivocally as a pun, not a misspelling or misapprehension.