You did "violate" the fan. My brother has one such fan, and it says not to replace the plug, but the whole appliance.
That's a $20-$25 plug, as all the box fans I've had fail had shorted and melted plugs, not a problem with the fan. And I DON'T buy $5-$10 no-name box fans.
Oh, and there was one that the cat chewed the cord while it was plugged in and shorted it.
Sorry, I was only kidding about the cut-the-plug and
sell them thing.
I DO have three with new plugs that I use in my room and in the garage windows when I spray paint.
Ian A.